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Merrill VD, Ward MD, Diaz-McNair J, Pickett EA, Duh SH, Christenson RH. Assessing Phlebotomy Device Preference and Specimen Quality in an Oncology Outpatient Clinic. J Appl Lab Med 2021; 7:532-540. [PMID: 34632493 DOI: 10.1093/jalm/jfab109] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022]
Abstract
BACKGROUND Oncology patients have frequent venipunctures, which causes scarring, making subsequent draws difficult and painful. Novel blood collection systems may decrease discomfort in patients experiencing repeat blood draws. METHODS Oncology outpatients (n = 101; criteria excluded 12) were recruited to determine their preference for either of two blood collection systems, the 23-gauge standard BD Vacutainer Push Button Blood Collection Set (Standard Push Button system) or the 25-gauge BD Vacutainer UltraTouch Push Button Blood Collection Set (UltraTouch Push Button system). Subjects received two blinded, randomized blood draws, one with each device and just one device for each arm. Subjects subsequently rated their blinded preference for blood collection system. Specimen quality was assessed for each device with measurements for plasma hemoglobin (Shimadzu UV-1800 spectrophotometer, Shimadzu), lactate dehydrogenase, and potassium (Vitros 4600/5600 analyzer, Ortho Diagnostics). RESULTS Preference for the 25-gauge UltraTouch Push Button system over the 23-gauge Standard Push Button system was significant (UltraTouch, n = 51; Standard n = 30; no preference, n = 8; P = 0.0196). Regarding sample quality, the 25-gauge UltraTouch Push Button system had significantly lower plasma hemoglobin (average 5.34 mg/dL) vs the 23-gauge Standard Push Button system (9.37 mg/dL; P < 0.0001); serum lactate dehydrogenase and potassium differences were not statistically significant. CONCLUSION Subjects in an oncology clinic preferred phlebotomy with the 25-gauge UltraTouch Push Button system, and samples using this device had less hemolysis as assessed by plasma hemoglobin.
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Affiliation(s)
- VeRonika D Merrill
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew D Ward
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jovita Diaz-McNair
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Elizabeth A Pickett
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Show-Hong Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
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Ward MD, Mullins KE, Pickett E, Merrill V, Ruiz M, Rebuck H, Duh SH, Christenson RH. Performance of 4 Automated SARS-CoV-2 Serology Assay Platforms in a Large Cohort Including Susceptible COVID-19-Negative and COVID-19-Positive Patients. J Appl Lab Med 2021; 6:942-952. [PMID: 33693808 PMCID: PMC7989439 DOI: 10.1093/jalm/jfab014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 02/26/2021] [Indexed: 01/05/2023]
Abstract
BACKGROUND Anti-SARS-CoV-2 serological responses may have a vital role in controlling the spread of the disease. However, the comparative performance of automated serological assays has not been determined in susceptible patients with significant comorbidities. METHODS In this study, we used large numbers of samples from patients who were negative (n = 2030) or positive (n = 112) for COVID-19 to compare the performance of 4 serological assay platforms: Siemens Healthineers Atellica IM Analyzer, Siemens Healthineers Dimension EXL Systems, Abbott ARCHITECT, and Roche cobas. RESULTS All 4 serology assay platforms exhibited comparable negative percentage of agreement with negative COVID-19 status ranging from 99.2% to 99.7% and positive percentage of agreement from 84.8% to 87.5% with positive real-time reverse transcriptase PCR results. Of the 2142 total samples, only 38 samples (1.8%) yielded discordant results on one or more platforms. However, only 1.1% (23/2030) of results from the COVID-19-negative cohort were discordant. whereas discordance was 10-fold higher for the COVID-19-positive cohort, at 11.3% (15/112). Of the total 38 discordant results, 34 were discordant on only one platform. CONCLUSIONS Serology assay performance was comparable across the 4 platforms assessed in a large population of patients who were COVID-19 negative with relevant comorbidities. The pattern of discordance shows that samples were discordant on a single assay platform, and the discordance rate was 10-fold higher in the population that was COVID-19 positive.
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Affiliation(s)
- Matthew D Ward
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristin E Mullins
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Elizabeth Pickett
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - VeRonika Merrill
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mark Ruiz
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Heather Rebuck
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Show-Hong Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
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Apple FS, Wu AHB, Sandoval Y, Sexter A, Love SA, Myers G, Schulz K, Duh SH, Christenson RH. Sex-Specific 99th Percentile Upper Reference Limits for High Sensitivity Cardiac Troponin Assays Derived Using a Universal Sample Bank. Clin Chem 2020; 66:434-444. [PMID: 32109298 DOI: 10.1093/clinchem/hvz029] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 10/23/2019] [Indexed: 01/29/2023]
Abstract
BACKGROUND How to select healthy reference subjects in deriving 99th percentiles for cardiac troponin assays still needs to be clarified. To assist with global implementation of high sensitivity (hs)-cardiac troponin (cTn) I and hs-cTnT assays in clinical practice, we determined overall and sex-specific 99th percentiles in 9 hs-cTnI and 3 hs-cTnT assays using a universal sample bank (USB). METHODS The Universal Sample Bank (USB) comprised healthy subjects, 426 men and 417 women, screened using a health questionnaire. Hemoglobin A1c (>URL 6.5%), NT-proBNP (>URL 125 ng/L) and eGFR (<60 mL/min), were used as surrogate biomarker exclusion criteria along with statin use. 99th percentiles were determined by nonparametric, Harrell--Davis bootstrap, and robust methods. RESULTS Subjects were ages 19 to 91 years, Caucasian 58%, African American 27%, Pacific Islander/Asian 11%, other 4%, Hispanic 8%, and non-Hispanic 92%. The overall and sex-specific 99th percentiles for all assays, before and after exclusions (n = 694), were influenced by the statistical method used, with substantial differences noted between and within both hs-cTnI and hs-cTnT assays. Men had higher 99th percentiles (ng/L) than women. The Roche cTnT and Beckman and Abbott cTnI assays (after exclusions) did not measure cTn values at ≥ the limit of detection in ≥50% women. CONCLUSIONS Our findings have important clinical implications in that sex-specific 99th percentiles varied according to the statistical method and hs-cTn assay used, not all assays provided a high enough percentage of measurable concentrations in women to qualify as a hs-assay, and the surrogate exclusion criteria used to define normality tended to lower the 99th percentiles.
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Affiliation(s)
- Fred S Apple
- Department of Laboratory Medicine & Pathology, Hennepin Healthcare/Hennepin Country Medical Center, Hennepin Healthcare Research Institute and University of Minnesota, Minneapolis, MN
| | - Alan H B Wu
- Department of Laboratory Medicine, University of California, San Francisco, CA
| | - Yader Sandoval
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Anne Sexter
- Chronic Disease Research Group, Hennepin Healthcare Research Institute, Minneapolis, MN
| | - Sara A Love
- Department of Laboratory Medicine & Pathology, Hennepin Healthcare/Hennepin Country Medical Center, Hennepin Healthcare Research Institute and University of Minnesota, Minneapolis, MN
| | | | - Karen Schulz
- Hennepin Healthcare Research Institute, Hennepin County Medical Center, Minneapolis, MN
| | - Show-Hong Duh
- Department of Pathology, University of Maryland Medical Center, Baltimore, MD
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Christenson RH, Duh SH, Mullins KE, LeClair MM, Grigorov IL, Peacock WF. Analytical and clinical characterization of a novel high-sensitivity cardiac troponin assay in a United States population. Clin Biochem 2020; 83:28-36. [PMID: 32485169 DOI: 10.1016/j.clinbiochem.2020.05.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 05/13/2020] [Accepted: 05/26/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND Cardiac troponin (cTn) is the keystone for diagnosis of acute myocardial infarction (AMI). We examined the analytical and clinical diagnostic characteristics of the ACCESS hsTnI assay in a United States (US) population. METHODS All measurements and studies were conducted using a lithium heparin matrix. Sex-specific 99th percentile upper reference limits (URLs) were determined for 1089 healthy women (54.6%) and men using non-parametric statistics. High-sensitivity (hs) performance was assessed to determine if the total CV was ≤10% at sex-specific URLs, and if ≥50% of cTnI values for each sex exceeded the assay's limit of detection (LoD). Precision, analytical measurement range, high-dose hook effect, and endogenous/exogenous interferences were examined with CLSI guidance. Clinical characterization included serial sampling of 1854 suspected AMI subjects presenting to 14 US Emergency Departments. AMI was adjudicated by a panel of expert cardiologists. The study's only exclusion was end stage renal disease. RESULTS 99th percentile URLs were 11.6-, 19.8- and 17.5-ng/L for respective female, male and all-subject populations. Total %CV was <8% from 6.8 to 19,000 ng/L, and <6% at sex-specific 99th percentiles; ≥99% of ACCESS hsTnI values for each sex exceeded the LoD. No high-dose hook effect or endogenous/exogenous interferences were identified. A comparison of Baseline samples collected at ≤1 h and any-time after presentation, found 4% lower sensitivity for AMI than with earlier sampling. For 1-9 h post presentation, the sensitivity was >90%, specificity >85%; and negative and positive predictive value were ≥99% and >60%, respectively. CONCLUSION Analytical and clinical performance of the ACCESS hsTnI assay meets the definition of a hs cTn method. The ACCESS hsTnI assay has good precision over a wide range, no significant interferences, and sensitivity >90% and NPV ≥99%. Performance is appropriate for aiding in AMI diagnosis.
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Affiliation(s)
- Robert H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States.
| | - Show-Hong Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Kristin E Mullins
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Margot M LeClair
- Beckman Coulter Inc., 1000 Lake Hazeltine Dr, Chaska, MN, United States
| | - Ilya L Grigorov
- Beckman Coulter Inc., 1000 Lake Hazeltine Dr, Chaska, MN, United States
| | - W Frank Peacock
- Department of Emergency Medicine, Baylor College of Medicine, Houston, TX, United States
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Christenson RH, Mullins K, Duh SH. Corrigendum to 'Validation of high-sensitivity performance for a United States Food and Drug Administration cleared cardiac troponin I assay' [Clin. Biochem. 56 (2018) 4-10]. Clin Biochem 2018; 58:132. [PMID: 29908760 DOI: 10.1016/j.clinbiochem.2018.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Robert H Christenson
- University of Maryland School of Medicine, Department of Pathology, 685 West Baltimore Street, MSTF Room 2-54, Baltimore, MD 21201, USA..
| | - Kristin Mullins
- University of Maryland School of Medicine, Department of Pathology, 685 West Baltimore Street, MSTF Room 2-54, Baltimore, MD 21201, USA
| | - Show-Hong Duh
- University of Maryland School of Medicine, Department of Pathology, 685 West Baltimore Street, MSTF Room 2-54, Baltimore, MD 21201, USA
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Christenson RH, Mullins K, Duh SH. Validation of high-sensitivity performance for a United States Food and Drug Administration cleared cardiac troponin I assay. Clin Biochem 2018; 56:4-10. [PMID: 29750939 DOI: 10.1016/j.clinbiochem.2018.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/30/2018] [Accepted: 05/06/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND High-Sensitivity (hs) cardiac troponin (cTn) assays are categorized by two criteria: (i) cTn values above the limit of detection (LoD) for >50% of male and female healthy cohorts of ≥300 individuals; (ii) imprecision ≤10% total %CV for sex-specific 99th-percentile clinical decision values (CDVs). No documented hs-Tn assay has yet been FDA-cleared. METHODS The PATHFAST cTnI-II assay's LoD was 2.3 ng/L using CLSI EP-17. The AACC Universal Sample Bank of 847 healthy men (50.6%) and women (49.4%) was used to determine 99th-percentile CDVs with Nonparametric, Harrell-Davis and Robust modeling. Health/Medication questionnaires and Amino-terminal proBNP, Hemoglobin A1c and estimated Glomerular Filtration Rate surrogates excluded underlying health conditions. RESULTS The cTnI-II test's total CV was 6.1% at 29 ng/L and 7.1% at 22 ng/L; the LoD was 2.3 ng/L. Of the full 847-member healthy cohort, 113 (13.3%) were excluded by abnormal surrogate biomarkers. The final 734-member healthy population had the following (% > LoD): overall, 487 (66.3%); women, 186 (52.8%); and men, 301 (78.8%). 99th-percentile CDVs by Nonparametric modeling were: 28 ng/L (90% CI: 20-30), overall final 732-member healthy population; 20 ng/L (90% CI: 13-30), 352 women; and 30 ng/L (90% CI: 21-37), 382 men. Differences between sex-specific CDVs were not significantly different (p > .05) with Nonparametric or Harrell-Davis modeling; however, Robust Modeling did show significance (<0.05), with lower CDVs at 11 ng/L (90% CI: 9-12) and 16 ng/L (90% CI: 15-18) for the female and male cohorts, respectively. CONCLUSIONS cTnI-II is the only FDA-cleared assay that has demonstrated high-sensitivity cTn assay. Use of recommended modeling in >300 healthy subjects for determining sex-specific 99th-percentile CDVs did not show statistically significant differences except with the Robust modeling.
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Affiliation(s)
- Robert H Christenson
- University of Maryland School of Medicine, Department of Pathology, 685 West Baltimore Street, MSTF Room 2-54, Baltimore, MD 21201, USA.
| | - Kristin Mullins
- University of Maryland School of Medicine, Department of Pathology, 685 West Baltimore Street, MSTF Room 2-54, Baltimore, MD 21201, USA
| | - Show-Hong Duh
- University of Maryland School of Medicine, Department of Pathology, 685 West Baltimore Street, MSTF Room 2-54, Baltimore, MD 21201, USA
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Duh SH. The Golden Age Revisited via Estradiol and LC-MS/MS. J Appl Lab Med 2016; 1:11-13. [PMID: 33626796 DOI: 10.1373/jalm.2016.020529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 05/11/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Show-Hong Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD
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deFilippi C, Seliger SL, Kelley W, Duh SH, Hise M, Christenson RH, Wolf M, Gaggin H, Januzzi J. Interpreting Cardiac Troponin Results from High-Sensitivity Assays in Chronic Kidney Disease without Acute Coronary Syndrome. Clin Chem 2012; 58:1342-51. [DOI: 10.1373/clinchem.2012.185322] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
Quantification and comparison of high-sensitivity (hs) cardiac troponin I (cTnI) and cTnT concentrations in chronic kidney disease (CKD) have not been reported. We examined the associations between hs cTnI and cTnT, cardiovascular disease, and renal function in outpatients with stable CKD.
METHODS
Outpatients (n = 148; 16.9% with prior myocardial infarction or coronary revascularization) with an estimated glomerular filtration rate (eGFR) of <60 mL · min−1 · (1.73 m2)−1 had serum cTnI (99th percentile of a healthy population = 9.0 ng/L), and cTnT (99th percentile = 14 ng/L) measured with hs assays. Left ventricular ejection fraction (LVEF) and mass were assessed by echocardiography, and coronary artery calcification (CAC) was determined by computed tomography. Renal function was estimated by eGFR and urine albumin/creatinine ratio (UACR).
RESULTS
The median (interquartile range) concentrations of cTnI and cTnT were 6.3 (3.4–14.4) ng/L and 17.0 (11.2–31.4) ng/L, respectively; 38% and 68% of patients had a cTnI and cTnT above the 99th percentile, respectively. The median CAC score was 80.8 (0.7–308.6), LV mass index was 85 (73–99) g/m2, and LVEF was 58% (57%–61%). The prevalences of prior coronary disease events, CAC score, and LV mass index were higher with increasing concentrations from both hs cardiac troponin assays (P < 0.05 for all). After adjustment for demographics and risk factors, neither cardiac troponin assay was associated with CAC, but both remained associated with LV mass index as well as eGFR and UACR.
CONCLUSIONS
Increased hs cTnI and cTnT concentrations are common in outpatients with stable CKD and are influenced by both underlying cardiac and renal disease.
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Affiliation(s)
| | | | - Walter Kelley
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD
| | - Show-Hong Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD
| | | | - Robert H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD
| | - Myles Wolf
- Department of Medicine, University of Miami, Miami, FL
| | - Hanna Gaggin
- Department of Medicine, Cardiology Division, Massachusetts General Hospital, Boston, MA
| | - James Januzzi
- Department of Medicine, Cardiology Division, Massachusetts General Hospital, Boston, MA
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Smith K, deFilippi C, Isakova T, Gutiérrez OM, Laliberte K, Seliger S, Kelley W, Duh SH, Hise M, Christenson R, Wolf M, Januzzi J. Fibroblast growth factor 23, high-sensitivity cardiac troponin, and left ventricular hypertrophy in CKD. Am J Kidney Dis 2012; 61:67-73. [PMID: 22883134 DOI: 10.1053/j.ajkd.2012.06.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 06/26/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND Detectable levels of cardiac troponins are common in individuals with chronic kidney disease (CKD), even in the absence of symptomatic cardiovascular disease. Abnormal cardiac troponin values are associated with coronary artery disease and left ventricular hypertrophy (LVH) and predict poor clinical outcomes. Elevated levels of fibroblast growth factor 23 (FGF-23) contribute to LVH in CKD. We investigated the association of FGF-23 and hs-cTnI (high-sensitivity cardiac troponin I) and hs-cTnT (high-sensitivity cardiac troponin T) levels in CKD and examined the role of LVH in this association. STUDY DESIGN Cross-sectional observational study. SETTING & PARTICIPANTS 153 stable outpatients with non-dialysis-dependent CKD. PREDICTOR The primary predictor was FGF-23 level. OUTCOMES hs-cTnI, hs-cTnT. MEASUREMENTS FGF-23, hs-cTnI, hs-cTnT; left ventricular mass index (LVMI) assessed by echocardiography; coronary artery calcification (CAC) measured by computed tomography. LVMI and CAC were evaluated as potential mediators of the effect of FGF-23 on hs-cTnI/T. RESULTS Mean age was 64 ± 12 (SD) years, mean estimated glomerular filtration rate was 34 ± 11 mL/min/1.73 m(2), median FGF-23 level was 120 (25th-75th percentile, 79-223) reference unit (RU)/mL, median hs-cTnI level was 6.5 (25th-75th percentile, 3.5-14.5) pg/mL, and median hs-cTnT level was 16.8 (25th-75th percentile, 11.1-33.9) pg/mL. cTnI and cTnT concentrations were higher than the 99th percentile of a healthy population in 42% and 61% of patients, respectively. In unadjusted and multivariable-adjusted analyses, hs-cTnI/T levels were associated significantly with FGF-23 levels. Adjusting for LVMI, but not CAC, weakened the association of FGF-23 and hs-cTnI/T levels. LIMITATIONS Vitamin D levels were not measured. The prevalence of coronary artery disease may have been underestimated because it was ascertained by self-report. CONCLUSIONS Minimally elevated cTnI and cTnT levels, detectable by high-sensitivity assays, are associated with elevated FGF-23 levels in stable outpatients with CKD. FGF-23-associated LVH may contribute to detectable hs-cTnI/T levels observed in non-dialysis-dependent patients with CKD.
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Affiliation(s)
- Kelsey Smith
- Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Christenson RH, Duh SH. Evidence based approach to practice guides and decision thresholds for cardiac markers. Scandinavian Journal of Clinical and Laboratory Investigation 2010. [DOI: 10.1080/00365519909168332] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Christenson RH, Azzazy HME, Duh SH, Maynard S, Seliger SL, Defilippi CR. Impact of increased body mass index on accuracy of B-type natriuretic peptide (BNP) and N-terminal proBNP for diagnosis of decompensated heart failure and prediction of all-cause mortality. Clin Chem 2010; 56:633-41. [PMID: 20167699 DOI: 10.1373/clinchem.2009.129742] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND BNP and N-terminal proBNP (NT-proBNP) concentrations may be depressed in patients with increased body mass index (BMI). Whether increased BMI affects accuracy of these biomarkers for diagnosing decompensated heart failure (HF) and predicting outcomes is unknown. METHODS We measured BNP and NT-proBNP in 685 patients with possible decompensated HF in a free-living community population subdivided by BMI as obese, overweight, and normal weight. HF diagnosis was adjudicated by a cardiologist blinded to BNP and NT-proBNP results. We tabulated all-cause mortality over a median follow-up of 401 days and assessed marker accuracy for HF diagnosis and mortality by ROC analysis. RESULTS Of the 685 patients, 40.9% were obese (n = 280), 28.2% were overweight (n = 193), and 30.9% had normal BMI (n = 212). Obese patients had lower BNP and NT-proBNP compared with overweight or normal-weight individuals (P < 0.001) and decreased mortality compared with normal-weight individuals (P < 0.001). Both biomarkers added significantly to a multivariate logistic regression model for diagnosis of decompensated HF across BMI categories. NT-proBNP outperformed BNP for predicting all-cause mortality in normal-weight individuals (chi(2) for BNP = 6.4, P = 0.09; chi(2) for NT-proBNP = 16.5, P < 0.001). Multivariate regression showed that both biomarkers remained significant predictors of decompensated HF diagnosis in each BMI subgroup. CONCLUSIONS In this study population, obese patients had significantly lower BNP and NT-proBNP that reflected lower mortality. BNP and NT-proBNP can be used in all BMI groups for decompensated HF diagnosis, although BMI-specific cutpoints may be necessary to optimize sensitivity.
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Affiliation(s)
- Robert H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Cervinski MA, Duh SH, Hock KG, Gray J, Wei TQ, Kilgore DC, Christenson RH, Scott MG. Performance characteristics of a no-pretreatment, random access sirolimus assay for the Dimension® RxL clinical chemistry system. Clin Biochem 2009; 42:1123-7. [DOI: 10.1016/j.clinbiochem.2009.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 03/05/2009] [Accepted: 03/06/2009] [Indexed: 11/30/2022]
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13
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Kelley WE, Lockwood CM, Cervelli DR, Sterner J, Scott MG, Duh SH, Christenson RH. Cardiovascular disease testing on the Dimension Vista system: biomarkers of acute coronary syndromes. Clin Biochem 2009; 42:1444-51. [PMID: 19523464 DOI: 10.1016/j.clinbiochem.2009.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 05/22/2009] [Accepted: 05/27/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Performance characteristics of the LOCI cTnI, CK-MB, MYO, NTproBNP and hsCRP methods on the Dimension Vista System were evaluated. DESIGN AND METHODS Imprecision (following CLSI EP05-A2 guidelines), limit of quantitation (cTnI), limit of blank, linearity on dilution, serum versus plasma matrix studies (cTnI), and method comparison studies were conducted. RESULTS Method imprecision of 1.8 to 9.7% (cTnI), 1.8 to 5.7% (CK-MB), 2.1 to 2.2% (MYO), 1.6 to 3.3% (NTproBNP), and 3.5 to 4.2% (hsCRP) were demonstrated. The manufacturer's claimed imprecision, detection limits and upper measurement limits were met. Limit of Quantitation was 0.040 ng/mL for the cTnI assay. Agreement of serum and plasma values for cTnI (r=0.99) was shown. Method comparison study results were acceptable. CONCLUSIONS The Dimension Vista cTnI, CK-MB, MYO, NTproBNP, and hsCRP methods demonstrate acceptable performance characteristics for use as an aid in the diagnosis and risk assessment of patients presenting with suspected acute coronary syndromes.
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Affiliation(s)
- Walter E Kelley
- Clinical Chemistry Labs, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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deFilippi CR, Thorn EM, Aggarwal M, Joy A, Christenson RH, Duh SH, Jeudy J, Beache G. Frequency and cause of cardiac troponin T elevation in chronic hemodialysis patients from study of cardiovascular magnetic resonance. Am J Cardiol 2007; 100:885-9. [PMID: 17719339 DOI: 10.1016/j.amjcard.2007.04.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 04/06/2007] [Accepted: 04/06/2007] [Indexed: 11/17/2022]
Abstract
Cardiac troponin T level predicts a gradient risk for death in patients using hemodialysis. We used cardiovascular magnetic resonance (CMR) to determine whether an asymptomatic increase of troponin T in patients using hemodialysis is associated with subclinical myocardial infarction (MI). Twenty-six patients using long-term hemodialysis (49 +/- 12 years of age, 19 men, 8 diabetics) with left ventricular (LV) ejection fraction >40% and no known coronary artery disease were selected based on a low-risk troponin T level </=0.03 ng/ml (median 0.02, interquartile range 0.00 to 0.02, n = 13) and high-risk troponin T level >/=0.07 ng/ml (median 0.15, interquartile range 0.09 to 0.19, n = 13). All underwent CMR imaging for LV mass and for MI by late gadolinium enhancement. Between high- and low-risk patients using hemodialysis, there were no differences in age, gender, ethnicity, or diabetes mellitus. Of the high-risk patients, 3 (23%, 95% confidence interval [CI] 5 to 54) had MI by late gadolinium enhancement versus 0 (0%, 95% CI 0 to 25) low-risk patients (p = 0.22). A diffuse, midwall late gadolinium enhancement pattern was seen in 1 high-risk patient (8%) versus 0 low-risk patient (0%, 95% CI 0 to 25, p = 0.97). Height-adjusted LV mass and LV hypertrophy were not significantly different between high-risk (62 +/- 26 g/m(2.7), LV hypertrophy, n = 7, 54%) and low-risk (54 +/- 20 g/m(2.7), LV hypertrophy, n = 5, 39%) patients (p = 0.37 for LV mass, p = 0.69 for LV hypertrophy). In conclusion, MI detected by CMR is present in few patients on hemodialysis with high troponin T levels and absent in the setting of very low troponin T levels, suggesting that additional myocardial pathologies cause increased troponin T in patients using hemodialysis.
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Affiliation(s)
- Christopher R deFilippi
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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15
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Griffey MA, Hock KG, Kilgore DC, Wei TQ, Duh SH, Christenson R, Scott MG. Performance of a no-pretreatment tacrolimus assay on the Dade Behring Dimension RxL clinical chemistry analyzer. Clin Chim Acta 2007; 384:48-51. [PMID: 17588555 DOI: 10.1016/j.cca.2007.05.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Revised: 05/17/2007] [Accepted: 05/20/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND Therapeutic drug monitoring for tacrolimus is important for organ transplant patients receiving this immunosuppressant. Current available assays for tacrolimus require sample pre-treatment and operate in a batch mode. Here a no-pretreatment tacrolimus assay, performed on the Dade Behring Dimension analyzer is compared to the Abbott IMx tacrolimus assay and to an LC/MS/MS method. METHODS Whole blood samples from 2 medical centers and different transplant types (kidney n=103, liver n=81, heart n=27, pancreas n=16, bone marrow n=9, [corrected] lung n=7), were obtained and tacrolimus quantified by each of the 3 assays. RESULTS The lower limit of the linear range was 1.2 ng/ml on the Dimension assay. Total imprecision was 9.8% and within-run imprecision was 9.6% at a tacrolimus concentration of 3.4 ng/dL. Passing-Bablock regression analysis determined the following relationships: DIMN=(1.16) LC/MS - 0.43, r=0.90 and DIMN=(0.99)IMx - 0.35, r=0.87. CONCLUSIONS The Dade Behring Dimension [corrected] Tacrolimus assay has adequate imprecision and correlates well with the reference method of LC/MS/MS. The assay appears suitable for clinical use, and has the advantages of not requiring a pretreatment step and the ability to be performed in a random-access mode.
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Affiliation(s)
- Megan A Griffey
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
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16
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Abstract
Many new technologies are being applied to measure blood glucose concentrations, but there is a lack of a standardized approach to evaluate performance of these devices. We sought to identify the key elements in evaluating the performance of devices for measuring blood glucose. We examined these elements in a multicenter study of four brands of glucose meters that are commonly used by diabetic patients. We tested control materials, spiked whole blood specimens, and 461 heparinized whole blood specimens in triplicate by each of the four brand glucose meters, and analyzed the plasma glucose concentrations of these specimens by a hexokinase (HK) method that incorporated reference materials developed by National Institute of Standards and Technology. Testing with glucose meters was performed at three sites, with multiple operators, meters, and representative lots of reagents. We evaluated the systematic bias, random error, and clinical significance of glucose meters. Meters were precise with a coefficient of variation of <4% across a wide range of glucose concentrations. Slopes significantly different from 1.0 were observed for two meters with 11-13% and -11% to -13% at the 95% confidence interval level by the linear regression of meter results versus the HK method from 33 to 481 mg/dL (correlation coefficient >0.98 and standard error of estimation S(y/x) <13 mg/dL for both meters). Analysis of the clinical significance of bias by Clarke Error Grid showed that results of the four meters were outside the accurate zone (26.5%, 2.4%, 1.5%, and 5.6%). Only a small number of the results showed clinically significant bias, mostly in the hypoglycemic range. Meters performed consistently throughout the study and, generally, were precise, although precision varied at extremely high or low glucose concentrations. Two of the glucose meters had substantial systematic bias when compared with an HK method, indicating a need for improving calibration and standardization. Analytical performance varied over the physiological range of glucose values so that separate accuracy and precision goals should be defined for hypoglycemic, normoglycemic, and hyperglycemic ranges. This study describes the current state of performance of blood glucose monitoring devices and points out those factors that should be assessed during evaluation of new devices.
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Affiliation(s)
- Ellen T Chen
- Center for Devices and Radiological Health, US Food and Drug Administration, Rockville, Maryland, USA
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17
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Christenson RH, Duh SH, Roe MT, Ohman EM. Determination of the falloff constant (k(f)) from modeling biochemical marker release: a new variable for discriminating therapies. Cardiovasc Toxicol 2002; 1:171-6. [PMID: 12213991 DOI: 10.1385/ct:1:2:171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new variable termed the falloff constant (k(f)) was derived from the curve fitting of serial CK-MB measurements. k(f) represents the rate constant of maximal decline in serum CK-MB and is determined from the slope of the lognormal curve at the inflection point. Physiologically, kf's magnitude reflects the balance between CK-MB's rate of release from tissue and the rate of elimination. We examined k(f) in two myocardial infarction (MI) patient sets. The first set was homogeneous and taken from the TAMI 7 study (n = 147) and included 111 patients having TIMI 2-3 flow after thrombolytic therapy and 36 patients who initially had TIMI 0-1 flow. The TIMI 0-1 patients were opened to TIMI 3 by angioplasty within 3 h. The second set consisted of 196 patients enrolled in the IMPACT-AMI study that demonstrated the efficacy of the glycoprotein (GP) IIb/IIIa antagonist eptifibatide. This second set consisted of 93 patients in the GP IIb/IIIa treatment group and 103 in the placebo group. Log-normal curve-fitting parameters including peak maximum and curve area were also compared to k(f) in the GP IIb/IIIa versus placebo set. The Wilcoxon test showed no difference between the two groups of TAMI 7 patients (p = 0.22). However, there was a highly significant difference in kf between the GP IIb/IIIa treatment group versus the placebo group (p = 0.0014). Both k(f) and peak maximum from curve fitting showed significant differences between the GP IIb/IIIa treatment group and the placebo group; however, k(f) showed a substantially lower p-value (p = 0.0014 and p = 0.023, respectively). As expected, k(f) showed no difference between the TAMI 7 groups because this was a homogeneous patient set in that they all had TIMI 3 patency status within 3 h of treatment. However, in the patient set having very different treatments, GP IIb/IIIa versus placebo, there was a highly significant difference in the kf variable. These data suggest that differences in reperfusion are reflected by kf and that this variable may represent a valuable new nonmortality end point derived from curve fitting analysis.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.
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18
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Nuwayhid I, McPhaul K, Bu-Khuzam R, Duh SH, Christenson RH, Keogh JP. Determinants of elevated blood lead levels among working men in Greater Beirut. J Med Liban 2001; 49:132-9. [PMID: 12184457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
This cross-sectional study reports the blood lead levels (BLL) among different working groups in Beirut and identifies the risk factors associated with elevated BLLs. A total of 579 men of 18 years of age or older (response rate 96%) working in Greater Beirut were interviewed. Of those, 315 (54.4%) provided a blood sample of which 291 were analyzed for lead. The mean BLL of the 134 men working in white-collar jobs (offices, retail shops) was 12.7 microg/dl (SD 3.7); statistically significantly lower than the mean BLL (18.4 microg/dl; SD 9.8) of the 157 men working in blue-collar occupations (such as gas station attendants, painters, mechanics). A blood lead level of 15 microg/dl or more was associated with blue-collar jobs, number of cigarettes smoked, commuting > or = 3 km to work, years in current occupation, and younger age. A BLL of at least 20 microg/dl was associated with eating lunch at work, in addition to blue-collar jobs, smoking, commuting, years of work, and younger age. The study findings suggest that environmental exposure (those not otherwise exposed to occupational lead) is mainly determined by smoking and exposure to leaded gasoline (commuting). Occupational exposure to lead is prevalent among a wide spectrum of Lebanese workers. Physicians are called upon to inquire more about the potential for lead exposure, especially among blue-collar workers. A policy action to improve working conditions and to phase out the use of leaded gasoline is recommended.
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Affiliation(s)
- I Nuwayhid
- Faculty of Health Sciences, American University of Beirut, Lebanon.
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19
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Christenson RH, Duh SH, Apple FS, Bodor GS, Bunk DM, Dalluge J, Panteghini M, Potter JD, Welch MJ, Wu AH, Kahn SE. Standardization of cardiac troponin I assays: round Robin of ten candidate reference materials. Clin Chem 2001; 47:431-7. [PMID: 11238293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND Cardiac troponin I (cTnI) results vary 100-fold among assays. As a step toward standardization, we examined the performance of 10 candidate reference materials (cRMs) in dilution studies with 13 cTnI measurement systems. METHODS Solutions of 10 cTnI cRMs, each characterized by NIST, were shipped to the manufacturers of 13 cTnI measurement systems. Manufacturers used their respective diluents to prepare each cRM in cTnI concentrations of 1, 10, 25, and 50 microg/L. For the purpose of ranking the cRMs, the deviation of each cTnI measurement from the expected response was assessed after normalization with the 10 microg/L cTnI solution. Normalized deviations were examined in five formats. Parameters from linear regression analysis of the measured cTnI vs expected values were also used to rank performance of the cRMs. RESULTS The three cRMs demonstrating the best overall rankings were complexes of troponins C, I, and T. The matrices for these three cRMs values differed; one was reconstituted directly from the lyophilized form submitted by the supplier; one was submitted in liquid form, lyophilized at NIST, and subsequently reconstituted; and the third was evaluated in the liquid form received from the supplier. The cRM demonstrating the fourth best performance was a binary complex of troponins C and I supplied in lyophilized form and reconstituted before distribution. CONCLUSIONS The cRMs demonstrating the best performance characteristics in 13 cTnI analytical systems will be included in subsequent activities of the cTnI Standardization Committee of the AACC.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, 22 S. Greene St., Baltimore, MD 21201, USA.
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20
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Christenson RH, Duh SH, Sanhai WR, Wu AH, Holtman V, Painter P, Branham E, Apple FS, Murakami M, Morris DL. Characteristics of an Albumin Cobalt Binding Test for assessment of acute coronary syndrome patients: a multicenter study. Clin Chem 2001; 47:464-70. [PMID: 11238298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND The ability of the N-terminal region of human albumin to bind cobalt is diminished by myocardial ischemia. The characteristics of an assay based on albumin cobalt binding were assessed in suspected acute coronary syndrome patients and in a control reference population. The ability of the Albumin Cobalt Binding (ACB) Test measurement at presentation to predict troponin-positive or -negative results 6-24 h later was also examined. METHODS We enrolled 256 acute coronary syndrome patients at four medical centers. Blood specimens were collected at presentation and then 6-24 h later. The dichotomous decision limit and performance characteristics of the ACB Test for predicting troponin-positive or -negative status 6 h-24 h later were determined using ROC curve analysis. Results for 32 patients could not be used because the time of onset of ischemia appeared to have been >3 h before presentation or was uncertain. The reference interval was determined by parametric analysis to estimate the upper 95th percentile of a reference population (n = 109) of ostensibly healthy individuals. RESULTS Increased cTnI was found in 35 of 224 patients. The ROC curve area for the ACB Test was 0.78 [95% confidence interval (CI), 0.70-0.86]. At the optimum decision point of 75 units/mL, the sensitivity and specificity of the ACB Test were 83% (95% CI, 66-93%) and 69% (95% CI, 62-76%). The negative predictive value was 96% (95% CI, 91-98%), and the positive predictive value was 33% (95% CI, 24-44%). The within-run CV of the ACB Test was 7.3%. Results for the reference population were normally distributed; the one-sided parametric 95th percentile was 80.2 units/mL. CONCLUSIONS This exploratory study suggests that the ACB Test has high negative predictive value and sensitivity in the presentation sample for predicting troponin-negative or -positive results 6-24 h later.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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21
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Beuerle JR, Azzazy HM, Apple FS, Duh SH, Tan A, Christenson RH. Performance characteristics of a new myoglobin microparticle enzyme immunoassay: a multicenter evaluation. Clin Biochem 2000; 33:595-8. [PMID: 11124348 DOI: 10.1016/s0009-9120(00)00168-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- J R Beuerle
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
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22
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Beuerle JR, Azzazy HM, Styba G, Duh SH, Christenson RH. Characteristics of myoglobin, carbonic anhydrase III and the myoglobin/carbonic anhydrase III ratio in trauma, exercise, and myocardial infarction patients. Clin Chim Acta 2000; 294:115-28. [PMID: 10727678 DOI: 10.1016/s0009-8981(99)00261-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Carbonic anhydrase III (CA III) is an enzyme present in skeletal muscle which is released into circulation following injury. Myoglobin (Mb) is a heme protein located in skeletal, smooth, and cardiac muscle which is also released after injury. Because CA III is not present in myocardium, combining serum CA III and Mb measurements may improve the specificity of Mb as an early diagnostic marker for myocardial infarction (MI) provided that a fixed ratio of Mb and CA III is released from skeletal muscle following cell injury. We examined release of Mb and CA III for exercise subjects (n=12), trauma patients (n=18), and MI patients (n=10) following emergency department admission. A fixed ratio of Mb/CA III had medians of 3.505 (range: 1.05-6.76) and 2.890 (range: 0.97-3.97) for exercise and trauma subjects, respectively, in samples collected within 5 h of the event. The Mb/CA III ratio was significantly higher (P<0.001) in MI patients (median: 35.395; range: 8.65-170.45) during this same time. This study confirmed that Mb and CA III are released in a fixed ratio following exercise, showed no significant difference in the ratio for trauma patients, and demonstrated significant ratio elevation for MI patients. These data suggest the ratio to be a useful diagnostic indicator of MI.
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Affiliation(s)
- J R Beuerle
- Department of Pathology, University of Maryland School of Medicine, 22 S. Greene Street, Baltimore, MD 21201, USA
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23
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Christenson RH, Vollmer RT, Ohman EM, Peck S, Thompson TD, Duh SH, Ellis SG, Newby LK, Topol EJ, Califf RM. Relation of temporal creatine kinase-MB release and outcome after thrombolytic therapy for acute myocardial infarction. TAMI Study Group. Am J Cardiol 2000; 85:543-7. [PMID: 11078264 DOI: 10.1016/s0002-9149(99)00808-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Measuring biochemical marker release after acute myocardial infarction helps in estimating infarct size and prognosis. We sought to relate in-hospital outcomes and curve-fitted creatine kinase (CK)-MB variables after thrombolysis. We measured CK-MB mass initially and at 30 and 90 minutes, and at 3, 8, and 20 hours after thrombolysis in 130 patients also undergoing cardiac catheterization at 90 minutes and at 5 to 7 days. Data were fitted, and maximums and curve areas calculated. CK-MB maximums related to infarct location (p = 0.014) and time to therapy (p = 0.002); curve area did not. Neither maximums nor curve area related to Thrombolysis in Myocardial Infarction trial flow grade at 90 minutes. Maximums related to ejection fraction at 90 minutes (p = 0.0004) and at 5 to 7 days (p = 0.0014), as did curve area (p = 0.0076 and 0.030, respectively). Maximums related to infarct zone function at 90 minutes (p = 0.024) and at 5 to 7 days (p = 0.042); curve area related only at 90 minutes (p = 0.027). Both maximums and curve area predicted congestive heart failure (p = 0.008 and p = 0.042, respectively) and a composite of congestive heart failure or death (p = 0.004 and p = 0.047, respectively); however, after adjusting for maximums, curve area no longer predicted congestive heart failure (p = 0.92). Maximums predicted the composite outcome after adjustment for curve area, and showed a trend toward predicting congestive heart failure (p = 0.089). We conclude that CK-MB maximums relate to infarct zone function, left ventricular function, and in-hospital outcomes after thrombolysis for acute myocardial infarction.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore.
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24
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Abstract
Often, in biomedical research, there are multiple sources of imperfect information regarding a dichotomous variable of interest. For example, in a study we are conducting on the relationship between cocaine use and stroke risk, information on the cocaine use of each study patient is available from three fallible sources: patient interviews; urine toxicology testing, and medical record review. Regression analyses based on a rule for classifying patients from this information can result in biased estimation of associations and variances due to the misclassification of some subjects and to the assumption of certainty. We describe a likelihood-based method that directly incorporates multiple sources of information regarding an outcome variable into a regression analysis and takes into account the uncertainty in the classification. The method can be applied when some sources of information are missing for some subjects. We show how the availability of multiple sources can be exploited to generate estimates of the quality (for example, sensitivity and specificity) of each source and to model the degree to which missing data are informative. A fitting algorithm and issues of identifiability are discussed. We illustrate the method using data from our study.
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Affiliation(s)
- L S Magder
- Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine Baltimore, MD 21201, USA
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25
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Christenson RH, Duh SH. Evidence based approach to practice guides and decision thresholds for cardiac markers. Scand J Clin Lab Invest Suppl 1999; 230:90-102. [PMID: 10389207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
There is substantial evidence for use of CK-MB, myoglobin, cardiac troponin T (cTnT) and cardiac troponin I (cTnI) for diagnosis of myocardial infarction (MI) and risk stratification of the acute coronary syndromes. Timing of specimen collection, patient population, and decision limits are important considerations. Serial CK-MB measurement must be considered a benchmark of cardiac markers. The National Heart Attack Alert Program (NHAAP) determined that high quality clinical trials show that serial CK-MB measurements are very accurate for diagnosis of MI and have large clinical impact. Meta-analysis of CK-MB mass for retrospective MI diagnosis yielded a clinical sensitivity of 96.8% and a specificity of 89.6% for sampling at 12-48 hours. Numerous studies of myoglobin have demonstrated a high negative predictive value and high sensitivity 2-6 hours after presentation. The NHAAP group, however, rated performance of myoglobin as modestly accurate with small clinical impact. cTnI has a clinical sensitivity and specificity for diagnosis of MI in the range of 90% and 97%, respectively. However decision limits for cTnI may differ by up to 10-fold for different assays, indicating need for standardization. Meta-analysis showed that cTnT had a sensitivity of 98.2% (CI: 97-99%) for diagnosis of MI with lower specificity due to detection of minor myocardial injury. Both cTnT and cTnI are more useful for stratifying risk in acute coronary syndrome patients than CK-MB mass. The predictive ability of both cTnT and cTnI is optimized by sampling > 6-12 hours after symptoms onset. But in unstable angina, the odds ratios for predicting outcomes of MI/short-term mortality with 12-24 hour sampling for cTnT was 2.7 the odds ratio for cTnI did not differ significantly at 4.2.
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Affiliation(s)
- R H Christenson
- Dept. of Pathology, Univ. of Maryland School of Medicine, Baltimore, USA.
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26
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Azzazy HM, Duh SH, Fitzgerald RL, McLawhon RW, Rosenthal M, Christenson RH. Multisite study of a second generation whole blood rapid assay for cardiac troponin T. Ann Clin Biochem 1999; 36 ( Pt 4):438-46. [PMID: 10456205 DOI: 10.1177/000456329903600406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We evaluated a second generation, qualitative, whole blood rapid assay for cardiac troponin T (cTnT), which employs a more cardio-specific troponin T mouse monoclonal capture antibody. Using quantitative cTnT enzyme-linked immunosorbent assay (ELISA) results as the benchmark for accuracy, we compared the performance of the second generation and the original whole blood rapid assays in 445 samples from patients with the following diagnoses, determined by medical record review: myocardial infarction, coronary bypass surgery, ischaemic heart disease, musculoskeletal disease, renal failure or other noncardiac conditions. Overall, concordance between the second generation cTnT Rapid Assay and the quantitative cTnT ELISA, compared using the McNemar test and a cut-off concentration of 0.1 microgram/L, was in the range 76-94% for each patient group. Using a receiver operating characteristic plot, the cut-off for the second generation cTnT Rapid Assay was in the range 0.06-0.08 microgram/L. We conclude that the second generation cTnT whole blood assay has a 2.5-fold lower analytical cut-off than the original rapid assay (0.2 microgram/L) and may represent a more sensitive clinical tool for the rapid triage and risk stratification of cardiac patients.
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Affiliation(s)
- H M Azzazy
- Department of Medical and Research Technology, University of Maryland School of Medicine, Baltimore 21201, USA.
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27
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Christenson RH, Demers LM, Goldsmith BM, Noel SA, Duh SH. Performance characteristics of the creatine kinase-MB mass assay on the Vitros ECi analyzer. Clin Biochem 1999; 32:237-40. [PMID: 10383088 DOI: 10.1016/s0009-9120(99)00008-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA.
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28
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Apple FS, Christenson RH, Valdes R, Andriak AJ, Berg A, Duh SH, Feng YJ, Jortani SA, Johnson NA, Koplen B, Mascotti K, Wu AHB. Simultaneous Rapid Measurement of Whole Blood Myoglobin, Creatine Kinase MB, and Cardiac Troponin I by the Triage Cardiac Panel for Detection of Myocardial Infarction. Clin Chem 1999. [DOI: 10.1093/clinchem/45.2.199] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
This multicenter study evaluated the Biosite Triage® Cardiac Panel as a quantitative, multimarker, whole blood system for the detection of acute myocardial infarction (MI). Optimum cutoffs for the discrimination of acute MI (n = 192 patients, 59 with MI) as determined by ROC curve analyses were as follows: 0.4 μg/L for cardiac troponin I (cTnI); 4.3 μg/L for the creatine kinase MB isoenzyme (CK-MB); and 107 μg/L for myoglobin. The Triage Panel showed the following concordances for detection or rule-out of MI compared with established devices: cTnI >89%; CK-MB >81%; myoglobin >69%. No significant differences were present between methods for the same marker. Diagnostic efficiencies demonstrated comparable sensitivities and specificities for the diagnosis of MI in patients presenting with symptoms compared with the Dade, Beckman, and Behring CK-MB, cTnI, and myoglobin assays; the ratio of sensitivity to specificity for each marker was as follows: cTnI, 98%:100%; CK-MB, 95%:91%; myoglobin, 81%:92%. The areas under the ROC curves for the Biosite myoglobin, CK-MB, and cTnI were 0.818, 0.905, and 0.970, respectively; the areas were significantly different, P <0.05. In patients with skeletal muscle injury and renal disease, the Triage cTnI showed 94% and 100% specificity, respectively. The Triage panel offers clinicians a whole blood, point-of-care analysis of multiple cardiac markers that provides excellent clinical sensitivity and specificity for the detection of acute MI.
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Affiliation(s)
- Fred S Apple
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
| | - Robert H Christenson
- Departments of Pathology and Medical Research Technology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Roland Valdes
- Department of Pathology and Laboratory Medicine, University of Louisville, School of Medicine, Louisville, KY 40292
| | - Alexander J Andriak
- Department of Pathology and Laboratory Medicine, University of Louisville, School of Medicine, Louisville, KY 40292
| | - Amy Berg
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
| | - Show-Hong Duh
- Departments of Pathology and Medical Research Technology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Yue-Jin Feng
- Department of Pathology, Hartford Hospital, Hartford, CT 06102
| | - Saeed A Jortani
- Department of Pathology and Laboratory Medicine, University of Louisville, School of Medicine, Louisville, KY 40292
| | - Nancy A Johnson
- Department of Pathology and Laboratory Medicine, University of Louisville, School of Medicine, Louisville, KY 40292
| | - Brenda Koplen
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
| | - Kristin Mascotti
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
| | - Alan HB Wu
- Department of Pathology, Hartford Hospital, Hartford, CT 06102
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Apple FS, Christenson RH, Valdes R, Andriak AJ, Berg A, Duh SH, Feng YJ, Jortani SA, Johnson NA, Koplen B, Mascotti K, Wu AH. Simultaneous rapid measurement of whole blood myoglobin, creatine kinase MB, and cardiac troponin I by the triage cardiac panel for detection of myocardial infarction. Clin Chem 1999; 45:199-205. [PMID: 9931041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
This multicenter study evaluated the Biosite Triage(R) Cardiac Panel as a quantitative, multimarker, whole blood system for the detection of acute myocardial infarction (MI). Optimum cutoffs for the discrimination of acute MI (n = 192 patients, 59 with MI) as determined by ROC curve analyses were as follows: 0.4 microgram/L for cardiac troponin I (cTnI); 4.3 microgram/L for the creatine kinase MB isoenzyme (CK-MB); and 107 microgram/L for myoglobin. The Triage Panel showed the following concordances for detection or rule-out of MI compared with established devices: cTnI >89%; CK-MB >81%; myoglobin >69%. No significant differences were present between methods for the same marker. Diagnostic efficiencies demonstrated comparable sensitivities and specificities for the diagnosis of MI in patients presenting with symptoms compared with the Dade, Beckman, and Behring CK-MB, cTnI, and myoglobin assays; the ratio of sensitivity to specificity for each marker was as follows: cTnI, 98%:100%; CK-MB, 95%:91%; myoglobin, 81%:92%. The areas under the ROC curves for the Biosite myoglobin, CK-MB, and cTnI were 0.818, 0.905, and 0.970, respectively; the areas were significantly different, P <0.05. In patients with skeletal muscle injury and renal disease, the Triage cTnI showed 94% and 100% specificity, respectively. The Triage panel offers clinicians a whole blood, point-of-care analysis of multiple cardiac markers that provides excellent clinical sensitivity and specificity for the detection of acute MI.
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Affiliation(s)
- F S Apple
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415, USA.
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Christenson R, Duh SH. Evidence based approach to practice guides and decision thresholds for cardiac markers. Scand J of Clinical & Lab Investigation 1999. [DOI: 10.3109/00365519909168332] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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31
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Christenson RH, Duh SH. Two of the authors of the article cited in the two preceding letters respond:. Clin Chem 1998. [DOI: 10.1093/clinchem/44.8.1789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
| | - Show-Hong Duh
- University of Maryland School of Medicine, Baltimore, MD 21201
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Azzazy HM, Chou PP, Tsushima JH, Troxil S, Gordon M, Avers RJ, Chiappetta E, Duh SH, Christenson RH. Abbott AxSYM Vancomycin II assay: multicenter evaluation and interference studies. Ther Drug Monit 1998; 20:202-8. [PMID: 9558135 DOI: 10.1097/00007691-199804000-00011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The authors evaluated the performance characteristics of the Abbott AxSYM Vancomycin II immunoassay in sera of patients with (n = 93 samples) and without (n = 327 patients) renal dysfunction. Correlation of vancomycin measurements with the Abbott AxSYM Vancomycin, Abbott TDx/TDxFLx, Syva enzyme-multiplied immunoassay technique (EMIT), DuPont automated chemistry analyzer (ACA), and high-performance liquid chromatography methods showed acceptable correlation as indicated by: slope values >0.95, r-values >0.97, y-intercepts <1.7 microg/ml, and S(y/x) ranging from 9% to 15% of the average vancomycin value. The AxSYM Vancomycin II assay showed acceptable correlation with AxSYM vancomycin, TDx/TDxFLx, and high-performance liquid chromatography methods in 93 samples from patients with renal dysfunction. This monoclonal antibody-based assay showed no apparent interference from the presence of human antimouse antibody (HAMA) or the microbiologically inactive vancomycin crystalline degradation product (CDP). The authors conclude that the AxSYM Vancomycin II assay showed satisfactory agreement with other methods tested in this study.
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Affiliation(s)
- H M Azzazy
- Department of Pathology, University of Maryland School of Medicine, Baltimore, USA
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33
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Christenson RH, Duh SH, Newby LK, Ohman EM, Califf RM, Granger CB, Peck S, Pieper KS, Armstrong PW, Katus HA, Topol EJ. Cardiac troponin T and cardiac troponin I: relative values in short-term risk stratification of patients with acute coronary syndromes. GUSTO-IIa Investigators. Clin Chem 1998; 44:494-501. [PMID: 9510853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We compared cardiac troponins T (cTnT) and I (cTnI) collected within 3.5 h of ischemic symptoms for predicting clinical outcomes in 770 patients. cTnT (cutoff > 0.1 microgram/L) and cTnI (cutoff > 1.5 micrograms/L) were concordant (both positive or negative) in 90.4% of patients. Among discordant results, 66 were cTnT positive and cTnI negative vs 8 who showed the reverse (P < 0.001). Five cTnT-positive and cTnI-negative patients died within 30 days; none who were cTnT negative and cTnI positive died. cTnT showed a slightly greater association (chi 2 = 18.0, P < 0.001) with 30-day mortality than cTnI (chi 2 = 12.5, P = 0.002). The area of the ROC curve for predicting 30-day mortality was significantly larger (Z = 2.08; P = 0.0375) for cTnT, at 0.68 [95% confidence interval (CI) 0.60-0.75], compared with cTnI, at 0.64 (95% CI 0.56-0.72). When cTnI and the electrocardiogram (ECG) were put in a logistic multiple regression model, cTnT added significant information (chi 2 = 8.03, P = 0.045); however, cTnI did not add to a model containing cTnT and the ECG (chi 2 = 0.84, P = 0.657). cTnT provided more information than cTnI for predicting 30-day mortality early after presentation with acute coronary syndromes.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, USA.
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34
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Christenson RH, Apple FS, Morgan DL, Alonsozana GL, Mascotti K, Olson M, McCormack RT, Wians FH, Keffer JH, Duh SH. Cardiac troponin I measurement with the ACCESS® immunoassay system: analytical and clinical performance characteristics. Clin Chem 1998. [DOI: 10.1093/clinchem/44.1.52] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractWe evaluated the ACCESS® cardiac troponin I (cTnI) immunoassay as a marker for myocardial infarction (MI). Total imprecision was 6.0% to 13.5%, the minimum detectable concentration was 0.007 μg/L, and the limit of quantitation was 0.046 μg/L. Comparison of cTnI measurement between the ACCESS and Stratus systems (n = 114) showed a proportional difference: ACCESS cTnI = 0.0996 Stratus cTnI + 0.049 μg/L (r = 0.811). Fifty-nine of 61 ambulatory patients without cardiac symptoms had no detectable cTnI (95% range, 0.00 to 0.025 μg/L). The optimum cutoff for discriminating MI (n = 289, 45 with MI) was 0.15 μg/L by receiver operator characteristic curve analysis; at this cutoff, the ACCESS cTnI assay showed a sensitivity of 88.9% (95% CI, 79.7–98.1%) and specificity of 91.8% (95% CI, 88.4–95.2%). The ACCESS cTnI assay results showed 89.4% and 93.0% concordance with the MB isoenzyme of creatine kinase (CK-MB) mass and Stratus cTnI results, respectively, for classification of patients with suspected MI. The ACCESS cTnI assay appears to show sensitivity and specificity comparable with those of both CK-MB mass and Stratus cTnI assays for the diagnosis of MI in patients presenting within 12 h of onset of symptoms.
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Affiliation(s)
- Robert H Christenson
- Departments of PathologyUniversity of Maryland School of Medicine, Baltimore, MD 21201
- Medical and Research Technology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Fred S Apple
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
| | - David L Morgan
- Clinical Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9072
| | - Gladys L Alonsozana
- Departments of PathologyUniversity of Maryland School of Medicine, Baltimore, MD 21201
| | - Kristin Mascotti
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
| | | | | | - Frank H Wians
- Clinical Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9072
| | - Joseph H Keffer
- Clinical Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9072
| | - Show-Hong Duh
- Departments of PathologyUniversity of Maryland School of Medicine, Baltimore, MD 21201
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35
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Christenson RH, Apple FS, Morgan DL, Alonsozana GL, Mascotti K, Olson M, McCormack RT, Wians FH, Keffer JH, Duh SH. Cardiac troponin I measurement with the ACCESS immunoassay system: analytical and clinical performance characteristics. Clin Chem 1998; 44:52-60. [PMID: 9550558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We evaluated the ACCESS cardiac troponin I (cTnI) immunoassay as a marker for myocardial infarction (MI). Total imprecision was 6.0% to 13.5%, the minimum detectable concentration was 0.007 microg/L, and the limit of quantitation was 0.046 microg/L. Comparison of cTnI measurement between the ACCESS and Stratus systems (n = 114) showed a proportional difference: ACCESS cTnI = 0.0996 Stratus cTnI + 0.049 microg/L (r = 0.811). Fifty-nine of 61 ambulatory patients without cardiac symptoms had no detectable cTnI (95% range, 0.00 to 0.025 microg/L). The optimum cutoff for discriminating MI (n = 289, 45 with MI) was 0.15 microg/L by receiver operator characteristic curve analysis; at this cutoff, the ACCESS cTnI assay showed a sensitivity of 88.9% (95% CI, 79.7-98.1%) and specificity of 91.8% (95% CI, 88.4-95.2%). The ACCESS cTnI assay results showed 89.4% and 93.0% concordance with the MB isoenzyme of creatine kinase (CK-MB) mass and Stratus cTnI results, respectively, for classification of patients with suspected MI. The ACCESS cTnI assay appears to show sensitivity and specificity comparable with those of both CK-MB mass and Stratus cTnI assays for the diagnosis of MI in patients presenting within 12 h of onset of symptoms.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA.
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36
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Alonsozana GL, Elfath MD, Mackenzie C, Gregory LC, Duh SH, Trump B, Christenson RH. In vitro interference of the red cell substitute pyridoxalated hemoglobin-polyoxyethylene with blood compatibility, coagulation, and clinical chemistry testing. J Cardiothorac Vasc Anesth 1997; 11:845-50. [PMID: 9412882 DOI: 10.1016/s1053-0770(97)90118-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Pyridoxalated hemoglobin-polyoxyethylene (PHP) is a prototypical red cell substitute approved for phase I studies. Peripheral blood smears of human blood mixed with PHP in 1 to 4 g/dL concentrations showed dose-dependent red cell aggregation and rouleaux. Whether this aggregation limits interpretation of blood compatibility testing and whether the intense coloration of serum or plasma containing PHP affects routine coagulation and clinical chemistry measurements was tested. DESIGN In vitro studies. SETTING University hospital laboratory. PARTICIPANTS Four healthy volunteers, blood types A, B, AB, and O. All were Rh+. MEASUREMENTS AND MAIN RESULTS ABO typing, Rh typing, and antibody screening and coagulation studies were performed on blood: PHP admixtures having final concentrations of 1, 2, and 4 g/dL. For clinical chemistry interference studies, known concentrations of analytes were added to a serum matrix containing PHP. ABO (forward) and Rh typing showed no interference in the three concentrations tested. Reverse ABO typing and antibody screening showed rouleaux at 4 g/dL, which corrected with routine saline replacement. Partial thromboplastin time (PTT), prothrombin time (PT), and fibrinogen showed no clinically significant differences from the controls. Results for electrolytes, renal function analytes, and markers of cardiac injury were acceptable by standard laboratory methods. However, results of liver function tests were unacceptable in PHP-containing specimens. CONCLUSIONS PHP-induced aggregation was observed with high PHP concentration; however, compatibility testing was not affected because agglutination was corrected by saline replacement, which is standard practice. Although routine blood banking, coagulation, and most clinical chemistry analytes can be measured reliably, alternative methods and strategies are needed for assessing liver function in the presence of PHP.
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Affiliation(s)
- G L Alonsozana
- Department of Pathology, School of Medicine, University of Maryland at Baltimore, USA
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37
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Christenson RH, Ohman EM, Topol EJ, Peck S, Newby LK, Duh SH, Kereiakes DJ, Worley SJ, Alosozana GL, Wall TC, Califf RM. Assessment of coronary reperfusion after thrombolysis with a model combining myoglobin, creatine kinase-MB, and clinical variables. TAMI-7 Study Group. Thrombolysis and Angioplasty in Myocardial Infarction-7. Circulation 1997; 96:1776-82. [PMID: 9323061 DOI: 10.1161/01.cir.96.6.1776] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Several biochemical markers have been investigated for the noninvasive assessment of reperfusion after myocardial infarction. Because myoglobin is released very soon after myocardial injury and clears rapidly after reperfusion, it may prove to be an excellent marker of occlusion and reperfusion. METHODS AND RESULTS We examined the relation between various myoglobin measures and Thrombolysis In Myocardial Infarction (TIMI) flow grade in 96 patients enrolled in a study of front-loaded thrombolysis who underwent 90-minute angiography. We also combined myoglobin measures with models that include clinical and creatine kinase-MB variables. The myoglobin level measured within 10 minutes of acute angiography showed the best overall performance and was used for later analyses. Of the clinical variables examined, only time from symptom onset to thrombolysis and chest pain grade at angiography discriminated among TIMI flow grades. Combining the 90-minute myoglobin level and these clinical variables showed a significant difference (P<.0001) between both TIMI 3 versus TIMI 0 through 2 and TIMI 2 or 3 versus TIMI 0 or 1 flow. When the 90-minute myoglobin level was added to an established predictive model containing clinical variables and creatine kinase-MB measures, its contribution remained significant (P=.044). The area under the receiver operator characteristic curve for this combined model was .88. CONCLUSIONS A single myoglobin measurement obtained 90 minutes after the start of thrombolysis, combined with select clinical variables and creatine kinase-MB levels, enhances the noninvasive prediction of reperfusion after myocardial infarction.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, USA
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Azzazy HME, Duh SH, Maturen A, Schaller E, Shaw L, Grimaldi R, Shock G, Christenson RH. Multicenter study of Abbott AxSYM® Digoxin II assay and comparison with 6 methods for susceptibility to digoxin-like immunoreactive factors. Clin Chem 1997. [DOI: 10.1093/clinchem/43.9.1635] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Abstract
Performance characteristics of the Abbott nonpretreatment AxSYM® Digoxin II assay were evaluated for quantification of digoxin at four independent sites. Correlation of digoxin measurements with the Abbott pretreatment AxSYM®, Baxter Stratus® II, Abbott TDx/TDxFLx II®, Abbott IMx®, Emit® 2000, and Beckman Synchron CX® digoxin assays showed acceptable agreement, as indicated by: slope values >0.84, r >0.90, y-intercepts for all comparisons at or below the assay detection limit, and Sy|x ranging between 7.5% and 15.4% of the average digoxin value. Susceptibility to interference from digoxin-like immunoreactive factors (DLIFs) was examined in 233 samples from renal patients, liver disease patients, cord blood, and third-trimester pregnancies; the AxSYM Digoxin II assay demonstrated the least DLIFs interference. DLIF susceptibility for four of the methods was significantly greater (P <0.05) than in the AxSYM Digoxin II assay; susceptibilities of the Stratus II and Emit 2000 methods were similar to the AxSYM Digoxin II assay.
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Affiliation(s)
- Hassan M E Azzazy
- Departments of Pathology
- Medical & Research Technology, University of Maryland School of Medicine, Baltimore, MD 21201
| | | | - Andrew Maturen
- Rush–Presbyterian–St. Lukes Medical Center, Chicago, IL 60612
| | | | - Leslie Shaw
- Hospital of the University of Pennsylvania, Philadelphia, PA 19104
| | | | - Gloria Shock
- Abbott Laboratories, Abbott North Park, IL 60064
| | - Robert H Christenson
- Departments of Pathology
- Medical & Research Technology, University of Maryland School of Medicine, Baltimore, MD 21201
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Azzazy HM, Duh SH, Maturen A, Schaller E, Shaw L, Grimaldi R, Shock G, Christenson RH. Multicenter study of Abbott AxSYM Digoxin II assay and comparison with 6 methods for susceptibility to digoxin-like immunoreactive factors. Clin Chem 1997; 43:1635-40. [PMID: 9299945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Performance characteristics of the Abbott nonpretreatment AxSYM Digoxin II assay were evaluated for quantification of digoxin at four independent sites. Correlation of digoxin measurements with the Abbott pretreatment AxSYM, Baxter Stratus II, Abbott TDx/ TDxFLx II, Abbott IMx, Emit 2000, and Beckman Synchron CX digoxin assays showed acceptable agreement, as indicated by: slope values > 0.84, r > 0.90, y-intercepts for all comparisons at or below the assay detection limit, and Sy/x ranging between 7.5% and 15.4% of the average digoxin value. Susceptibility to interference from digoxin-like immunoreactive factors (DLIFs) was examined in 233 samples from renal patients, liver disease patients, cord blood, and third-trimester pregnancies; the AxSYM Digoxin II assay demonstrated the least DLIFs interference. DLIF susceptibility for four of the methods was significantly greater (P < 0.05) than in the AxSYM Digoxin II assay; susceptibilities of the Stratus II and Emit 2000 methods were similar to the AxSYM Digoxin II assay.
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Affiliation(s)
- H M Azzazy
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA.
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40
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Christenson RH, Fitzgerald RL, Ochs L, Rozenberg M, Frankel WL, Herold DA, Duh SH, Alonsozana GL, Jacobs E. Characteristics of a 20-minute whole blood rapid assay for cardiac troponin T. Clin Biochem 1997; 30:27-33. [PMID: 9056106 DOI: 10.1016/s0009-9120(96)00132-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES A qualitative whole blood rapid assay for cardiac troponin T (cTnT) was examined. The assay uses the same antibodies as for a benchmark ELISA, but the capture and detection roles were switched to enhance specificity. DESIGN AND METHODS The cTnT Rapid Assay and ELISA were compared in 643 samples from patients having myocardial infarction, coronary artery bypass surgery, ischemic heart disease, musculoskeletal disease, renal failure, or other noncardiac conditions. Concordance between the methods was compared using the McNemar Test and cTnT cutoff of 0.2 micrograms/L. RESULTS For the "cutoff" of 0.2 micrograms/L, concordance between the cTnT Rapid Assay and ELISA was in the range of 90-95% for each group except the renal failure patients, where concordance was 77.9%. There was no significant difference between the cTnT Rapid Assay and ELISA, except in the renal failure and ischemic heart disease patients, where there was a greater number (p < 0.05) of cTnT Rapid Assay negative results when the ELISA was > 0.2 micrograms/L. Overall concordance between the cTnT Rapid Assay and CK-MBmass was 78%. CONCLUSION The McNemar test indicated that the cutoff for the cTnT Rapid Assay was 0.2 micrograms/L. Evidently the lower concordance among renal failure and ischemic heart disease patients reflects higher cTnT specificity for the Rapid Assay that was conferred by switching the capture and detection antibodies.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
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41
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Christenson RH, Ohman EM, Topol EJ, O'Hanesian MA, Sigmon KN, Duh SH, Kereiakes D, Worley SJ, George BS, Pizzo CK. Creatine kinase MM and MB isoforms in patients receiving thrombolytic therapy and acute angiography. TAMI Study Group. Clin Chem 1995; 41:844-52. [PMID: 7768002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Creatine kinase isoforms markers, including MB2 concentration, MB2/MB1 and MM3/MM1 ratios, and MT index (based on the "tissue" M subunits), were measured in serial specimens from 207 patients receiving thrombolytic therapy followed by acute angiography. The slope of release showed a significant relation (P < 0.05) between MB2 concentrations and patency, graded as TIMI 0 through TIMI 3; with regard to the precatheterization/baseline ratio, the MB2 concentrations, the MM3/MM1 ratio, and the MT index were all significantly related to graded patency (P < 0.004). Patients having patency graded as either TIMI 2/3 (Open) or TIMI 0/1 (Closed) showed highly significant differences (P < 0.03) in the slope of release and precatheterization/baseline ratio for all markers except the MB2/MB1 ratio. Defining Open as TIMI 3 and Closed as TIMI 0/1/2 showed very similar results. Despite these significant differences between the Open and Closed groups after thrombolytic therapy, none of the C index calculations (areas under ROC curves) for any of the isoform markers--either alone or combined--exceeded 0.70, suggesting that these markers have limited diagnostic utility for assessing patency.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
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42
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Christenson RH, Ohman EM, Topol EJ, O'Hanesian MA, Sigmon KN, Duh SH, Kereiakes D, Worley SJ, George BS, Pizzo CK. Creatine kinase MM and MB isoforms in patients receiving thrombolytic therapy and acute angiography. TAMI Study Group. Clin Chem 1995. [DOI: 10.1093/clinchem/41.6.844] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Creatine kinase isoforms markers, including MB2 concentration, MB2/MB1 and MM3/MM1 ratios, and MT index (based on the "tissue" M subunits), were measured in serial specimens from 207 patients receiving thrombolytic therapy followed by acute angiography. The slope of release showed a significant relation (P < 0.05) between MB2 concentrations and patency, graded as TIMI 0 through TIMI 3; with regard to the precatheterization/baseline ratio, the MB2 concentrations, the MM3/MM1 ratio, and the MT index were all significantly related to graded patency (P < 0.004). Patients having patency graded as either TIMI 2/3 (Open) or TIMI 0/1 (Closed) showed highly significant differences (P < 0.03) in the slope of release and precatheterization/baseline ratio for all markers except the MB2/MB1 ratio. Defining Open as TIMI 3 and Closed as TIMI 0/1/2 showed very similar results. Despite these significant differences between the Open and Closed groups after thrombolytic therapy, none of the C index calculations (areas under ROC curves) for any of the isoform markers--either alone or combined--exceeded 0.70, suggesting that these markers have limited diagnostic utility for assessing patency.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - E M Ohman
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - E J Topol
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - M A O'Hanesian
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - K N Sigmon
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - S H Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - D Kereiakes
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - S J Worley
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - B S George
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
| | - C K Pizzo
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201, USA
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Abstract
Total thyroxine (TT4), tracer uptake, thyroid-stimulating hormone (TSH), and free T4 (FT4) testing was examined in the ACS 180, Abbott IMx, and Stratus II systems. TSH sensitivity studies demonstrated that the ACS and IMx are second-generation assays; the Stratus showed between first- and second-generation performance. Except for one control below the detection limit, TSH imprecision was 3-10%. TSH accuracy was adequate for all systems. TT4 imprecision was 4-7%, except for the lowest control with the Stratus (18%). TT4 method agreement showed bias of about 20% between the systems. TT4 accuracy was compromised at the low end for the Stratus II, but was satisfactory otherwise. FT4 imprecision was 20% for the Stratus, < 5% for the IMx and 6% for the ACS. Uptake assays showed imprecision of 5-10%. The laboratory diagnosis indicated by each system's FT4 and calculated FT4 Index results were compared to determine diagnostic accuracy. In routine specimens, different clinical classifications were observed for 25% of specimens with the ACS, 19% with the Stratus, and 7% with the IMx; in the altered protein group, the Stratus showed 9% discordant results, the ACS showed 3%, and the IMx 0%. Of the three systems examined here, the Abbott IMx system showed the best overall performance.
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Affiliation(s)
- R H Christenson
- Department of Pathology, University of Maryland, School of Medicine, Baltimore, USA
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Abstract
Abstract
We examined the analytical performance of eight compact systems for measuring total cholesterol: AccuMeter, Cobas Ready, Discovery f2, DT60, L-D-X, Reflotron, QCA, and Vision. We determined average bias at two decision levels, the mean absolute bias, and the percentage of results differing from the comparison method results by > 8.9% allowable total error limit for multiple reagent lots. Average bias was < 3% for all lots tested for AccuMeter, Discovery f2, and DT60, but > 3% for one or more lots or sample types tested with the other systems. Of results from each reagent lot, > 95% were within the 8.9% total error specifications with Discovery f2, DT60, and QCA, whereas the performance of L-D-X, Vision, and Reflotron depended on reagent lot and (or) sample type. Of all results from each lot tested with AccuMeter and Cobas Ready, > 5% exceeded the total allowable error limit. We determined imprecision for five systems: Cobas Ready, Discovery f2, and QCA had CVs < 3%, whereas CVs for AccuMeter and L-D-X were > 3% but < 5%.
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Affiliation(s)
- L C Gregory
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201
| | - S H Duh
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201
| | - R H Christenson
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201
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Gregory LC, Duh SH, Christenson RH. Eight compact analysis systems evaluated for measuring total cholesterol. Clin Chem 1994; 40:579-85. [PMID: 8149614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We examined the analytical performance of eight compact systems for measuring total cholesterol: AccuMeter, Cobas Ready, Discovery f2, DT60, L-D-X, Reflotron, QCA, and Vision. We determined average bias at two decision levels, the mean absolute bias, and the percentage of results differing from the comparison method results by > 8.9% allowable total error limit for multiple reagent lots. Average bias was < 3% for all lots tested for AccuMeter, Discovery f2, and DT60, but > 3% for one or more lots or sample types tested with the other systems. Of results from each reagent lot, > 95% were within the 8.9% total error specifications with Discovery f2, DT60, and QCA, whereas the performance of L-D-X, Vision, and Reflotron depended on reagent lot and (or) sample type. Of all results from each lot tested with AccuMeter and Cobas Ready, > 5% exceeded the total allowable error limit. We determined imprecision for five systems: Cobas Ready, Discovery f2, and QCA had CVs < 3%, whereas CVs for AccuMeter and L-D-X were > 3% but < 5%.
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Affiliation(s)
- L C Gregory
- Department of Pathology, University of Maryland School of Medicine, Baltimore 21201
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