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Flowers KC, Shipman KE. Pitfalls in the Diagnosis and Management of Hypercortisolism (Cushing Syndrome) in Humans; A Review of the Laboratory Medicine Perspective. Diagnostics (Basel) 2023; 13:diagnostics13081415. [PMID: 37189516 DOI: 10.3390/diagnostics13081415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/28/2023] [Accepted: 04/11/2023] [Indexed: 05/17/2023] Open
Abstract
Biochemical confirmation of a diagnosis of hypercortisolism (Cushing syndrome) is vital to direct further investigations, especially given the overlap with non-autonomous conditions, such as pseudo-Cushing, and the morbidity associated with missed diagnoses. A limited narrative review was performed focusing on the laboratory perspective of the pitfalls of making a biochemical diagnosis of hypercortisolism in those presenting with presumed Cushing syndrome. Although analytically less specific, immunoassays remain cheap, quick, and reliable in most situations. Understanding cortisol metabolism can help with patient preparation, specimen selection (e.g., consideration of urine or saliva for those with possible elevations of cortisol binding globulin concentration), and method selection (e.g., mass spectrometry if there is a high risk of abnormal metabolites). Although more specific methods may be less sensitive, this can be managed. The reduction in cost and increasing ease of use makes techniques such as urine steroid profiles and salivary cortisone of interest in future pathway development. In conclusion, the limitations of current assays, particularly if well understood, do not impede diagnosis in most cases. However, in complex or borderline cases, there are other techniques to consider to aid in the confirmation of hypercortisolism.
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Affiliation(s)
- Kade C Flowers
- Department of Clinical Chemistry, University Hospitals Sussex NHS Trust, Worthing BN11 2DH, UK
| | - Kate E Shipman
- Department of Clinical Chemistry, University Hospitals Sussex NHS Trust, Worthing BN11 2DH, UK
- Department of Medical Education, Brighton and Sussex Medical School, University of Sussex, Falmer Campus, Brighton BN1 9PX, UK
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2
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Jiang W, Jones JC, Shankavaram U, Sproull M, Camphausen K, Krauze AV. Analytical Considerations of Large-Scale Aptamer-Based Datasets for Translational Applications. Cancers (Basel) 2022; 14:2227. [PMID: 35565358 PMCID: PMC9105298 DOI: 10.3390/cancers14092227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/17/2022] Open
Abstract
The development and advancement of aptamer technology has opened a new realm of possibilities for unlocking the biocomplexity available within proteomics. With ultra-high-throughput and multiplexing, alongside remarkable specificity and sensitivity, aptamers could represent a powerful tool in disease-specific research, such as supporting the discovery and validation of clinically relevant biomarkers. One of the fundamental challenges underlying past and current proteomic technology has been the difficulty of translating proteomic datasets into standards of practice. Aptamers provide the capacity to generate single panels that span over 7000 different proteins from a singular sample. However, as a recent technology, they also present unique challenges, as the field of translational aptamer-based proteomics still lacks a standardizing methodology for analyzing these large datasets and the novel considerations that must be made in response to the differentiation amongst current proteomic platforms and aptamers. We address these analytical considerations with respect to surveying initial data, deploying proper statistical methodologies to identify differential protein expressions, and applying datasets to discover multimarker and pathway-level findings. Additionally, we present aptamer datasets within the multi-omics landscape by exploring the intersectionality of aptamer-based proteomics amongst genomics, transcriptomics, and metabolomics, alongside pre-existing proteomic platforms. Understanding the broader applications of aptamer datasets will substantially enhance current efforts to generate translatable findings for the clinic.
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Affiliation(s)
- Will Jiang
- Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 9000 Rockville Pike, Building 10, CRC, Bethesda, MD 20892, USA; (W.J.); (U.S.); (M.S.); (K.C.)
| | - Jennifer C. Jones
- Translational Nanobiology Section, Laboratory of Pathology, NIH/NCI/CCR, Bethesda, MD 20892, USA;
| | - Uma Shankavaram
- Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 9000 Rockville Pike, Building 10, CRC, Bethesda, MD 20892, USA; (W.J.); (U.S.); (M.S.); (K.C.)
| | - Mary Sproull
- Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 9000 Rockville Pike, Building 10, CRC, Bethesda, MD 20892, USA; (W.J.); (U.S.); (M.S.); (K.C.)
| | - Kevin Camphausen
- Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 9000 Rockville Pike, Building 10, CRC, Bethesda, MD 20892, USA; (W.J.); (U.S.); (M.S.); (K.C.)
| | - Andra V. Krauze
- Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 9000 Rockville Pike, Building 10, CRC, Bethesda, MD 20892, USA; (W.J.); (U.S.); (M.S.); (K.C.)
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3
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Rappold BA. Review of the Use of Liquid Chromatography-Tandem Mass Spectrometry in Clinical Laboratories: Part I-Development. Ann Lab Med 2022; 42:121-140. [PMID: 34635606 PMCID: PMC8548246 DOI: 10.3343/alm.2022.42.2.121] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/25/2021] [Accepted: 09/28/2021] [Indexed: 11/19/2022] Open
Abstract
The process of method development for a diagnostic assay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) involves several disparate technologies and specialties. Additionally, method development details are typically not disclosed in journal publications. Method developers may need to search widely for pertinent information on their assay(s). This review summarizes the current practices and procedures in method development. Additionally, it probes aspects of method development that are generally not discussed, such as how exactly to calibrate an assay or where to place quality controls, using examples from the literature. This review intends to provide a comprehensive resource and induce critical thinking around the experiments for and execution of developing a clinically meaningful LC-MS/MS assay.
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Affiliation(s)
- Brian A. Rappold
- Laboratory Corporation of America Holdings, Research Triangle Park, NC, USA
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4
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Nouri MZ, Kroll KJ, Webb M, Denslow ND. Quantification of steroid hormones in low volume plasma and tissue homogenates of fish using LC-MS/MS. Gen Comp Endocrinol 2020; 296:113543. [PMID: 32598883 PMCID: PMC7447131 DOI: 10.1016/j.ygcen.2020.113543] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/23/2020] [Accepted: 06/16/2020] [Indexed: 02/06/2023]
Abstract
Quantification of steroid hormones in fish is an important step for toxicology and endocrinology studies. Among the hormone analysis techniques, liquid chromatography tandem mass spectrometry (LC-MS/MS) has widely been used for measuring hormones in various biological samples. Despite all improvements in the technique, detection of several hormones in a low volume of serum or plasma is still challenging. We developed a robust method for simultaneous quantification of 14 steroid hormones including corticosterone, cortisol, 11-ketotestosterone, progesterone, testosterone, 17OH-progesterone, aldosterone, dihydrotestosterone, estrone, 17β-estradiol, estriol, ethinylestradiol, levonorgestrel and equilin from volumes as low as 10 µL serum or plasma in a short run by LC-MS/MS. The lowest limit of detection in 10 µL serum was 0.012 ng/mL measured for cortisol, progesterone, testosterone, 17OH-progesterone and estrone. Use of high (25 times more) serum volume improved detection limit of hormones by 2-40 times. The method was compared with the radioimmunoassay technique in which testosterone and 17β-estradiol were highly correlated with R2 of 0.95 and 0.96, respectively. We validated the method by measuring four selected hormones, in low and high plasma volumes of largemouth bass (Micropterus salmoides). In addition, we developed a method to quantify hormones in whole body fish homogenates of small fish and compared the values to plasma concentrations, using fathead minnow (Pimephales promelas). Calculated concentrations of the hormones in plasma were consistent with those in the homogenate and 11-ketotestosterone and 17β-estradiol were significantly different in males and females. The ability to measure hormones from whole body homogenates was further evaluated in two model small fish species, zebrafish (Danio rerio) and juvenile silverside (Menidia beryllina). These results suggest that whole tissue homogenate is a reliable alternative for hormone quantification when sufficient plasma is not available.
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Affiliation(s)
- Mohammad-Zaman Nouri
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States.
| | - Kevin J Kroll
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
| | - Molly Webb
- USFWS, Bozeman Fish Technology Center, Bozeman, MT 59517, United States
| | - Nancy D Denslow
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
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5
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Benzi JRDL, Moreira FDL, Marques MP, Duarte G, Suarez-Kurtz G, Lanchote VL. A background subtraction approach for determination of endogenous cortisol and 6β-hydroxycortisol in urine by UPLC-MS/MS with application in a within-day variability study in HIV-infected pregnant women. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1144:122074. [PMID: 32247187 DOI: 10.1016/j.jchromb.2020.122074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 11/27/2022]
Abstract
Different methods have been used for CYP3A phenotyping, such as probe drugs or the urinary index 6β-hydroxycortisol/cortisol ratio (6β-OHF:C). This work describes a simple and affordable method for the simultaneous determination of the endogenous compounds cortisol and 6β-hydroxycortisol in urine using a background subtraction approach. The method was applied to investigate the CYP3A activity in HIV-infected pregnant women (n = 9) in the third trimester and postpartum periods. Also, the within-day variability in the 6β-OHF:C index was also evaluated. The sample preparation consists of a pre-cleanup with acetonitrile followed by liquid-liquid extraction with ethyl acetate. The analytes were resolved by employing an Acquity UPLC®BEH C18 column with a mobile phase that consisted of a mixture of acetonitrile containing 0.1% formic acid and 0.1% formic acid in gradient mode. The method presented linearities of 1-1.000 ng/mL and 2-1.000 ng/mL for C and 6β-OHF, respectively, and presented acceptable precision and accuracy. Qualitative and quantitative matrix effects tests were also performed. A high 6β-OHF:C within-day variability was observed in both phases. In the third trimester period, the 6β-OHF:C ranged from 2.57 to 51.69, with a mean ± standard deviation (SD) of 15.12 ± 5.41 (n = 9). Similar values were obtained in the postpartum period, with 6β-OHF:C ranging from 3.48 to 44.54 with a mean ± SD of 14.37 ± 5.73 (n = 7). Even though the 6β-OHF:C is a non-invasive index for CYP3A phenotyping, its use is susceptible to high within-day variability.
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Affiliation(s)
- Jhohann Richard de Lima Benzi
- Department of Clinical, Toxicological and Bromatological Analyses, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Fernanda de Lima Moreira
- Department of Clinical, Toxicological and Bromatological Analyses, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Maria Paula Marques
- Department of Clinical, Toxicological and Bromatological Analyses, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Geraldo Duarte
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Vera Lucia Lanchote
- Department of Clinical, Toxicological and Bromatological Analyses, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Zhang T, Zhao H, Li M, Zeng J, Wang J, Long Q, Wang Y, Zhang C, Chen W. Development and validation of a candidate reference method for serum cortisol by isotope dilution liquid chromatography-tandem mass spectrometry combined with dextran sulfate-Mg2+ precipitation. Anal Bioanal Chem 2020; 412:1325-1333. [DOI: 10.1007/s00216-019-02356-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/04/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022]
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7
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Hirano R, Yokokawa A, Furuta T, Shibasaki H. Sensitive and simultaneous quantitation of 6β-hydroxycortisol and cortisol in human plasma by LC-MS/MS coupled with stable isotope dilution method. JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:665-674. [PMID: 29766610 DOI: 10.1002/jms.4200] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
CYP3A phenotyping provides a means for personalized drug therapy. We focused our attention on the plasma 6β-hydroxycortisol (6β-OHF) to cortisol ratio as an index for CYP3A phenotyping. In the present study, we developed a sensitive and reliable method for the simultaneous determination of 6β-OHF and cortisol in human plasma using high-performance liquid chromatography/tandem mass spectrometry together with picolinylester derivatization or nonderivatization methods and 6β-[9,11,12,12-2 H4 ]hydroxycortisol and [1,2,4,19-13 C4 ]cortisol as internal standards for in vivo CYP3A phenotyping in humans. The lower limits of quantification were 38.513 pg/mL for 6β-OHF and 38.100 pg/mL for cortisol. The relative error and relative standard deviation of the lower limits of quantification were <5% for both methods. The intra-day and inter-day assay reproducibilities of the determined 6β-OHF and cortisol concentrations were consistent with the actual amounts added as relative errors and relative standard deviations for both methods, which were <5.4% and <3.9%, respectively. Both methods were applied for the quantification of plasma 6β-OHF and cortisol concentrations in healthy subjects taking oral contraceptives. The absolute concentrations and time course of 6β-OHF and cortisol were found to be consistent when measured using the 2 methods. The ratio as an index for in vivo CYP3A activity decreased after 21 days of taking oral contraceptives for both methods. To the best of our knowledge, this is the first study reporting the detailed investigation of accuracy and precision in the simultaneous measurement of 6β-OHF and cortisol in human plasma using liquid chromatography/tandem mass spectrometry coupled with stable isotope dilution method, which can be applied to CYP3A phenotyping.
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Affiliation(s)
- Ryohei Hirano
- Department of Medicinal Chemistry and Clinical Pharmacy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Akitomo Yokokawa
- Department of Medicinal Chemistry and Clinical Pharmacy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Takashi Furuta
- Department of Medicinal Chemistry and Clinical Pharmacy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Hiromi Shibasaki
- Department of Medicinal Chemistry and Clinical Pharmacy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
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8
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Galligan TM, Schwacke LH, Houser DS, Wells RS, Rowles T, Boggs ASP. Characterization of circulating steroid hormone profiles in the bottlenose dolphin (Tursiops truncatus) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gen Comp Endocrinol 2018; 263:80-91. [PMID: 29627396 PMCID: PMC6668333 DOI: 10.1016/j.ygcen.2018.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/26/2018] [Accepted: 04/02/2018] [Indexed: 10/17/2022]
Abstract
Systemic steroid hormone measurements are often used in the assessment of reproductive, developmental, and stress physiology in vertebrates. In protected wildlife, such as the common bottlenose dolphin (Tursiops truncatus), these measures can provide critical information about health and fitness to aid in effective conservation and management. Circulating steroid hormone concentrations are typically measured by immunoassays, which have imperfect specificity and are limited to the measurement of a single hormone per assay. Here we demonstrate that reverse phase solid phase extraction (SPE) coupled to liquid chromatography tandem mass spectrometry (LC-MS/MS) allows for the simultaneous, precise (<15% relative standard deviation), and accurate (between 70% and 120% recovery of spiked quantities) measurement of at least seven steroid hormones in dolphin plasma. These seven steroid hormones include three hormones that have been measured previously in bottlenose dolphin blood (progesterone, testosterone, and cortisol) and three hormones which have never been quantified in dolphin blood (17-hydroxyprogesterone, androstenedione, cortisone, and corticosterone). While 17β-estradiol was not detected endogenously, we were able to accurately and precisely measure spiked quantities estradiol. Measures from plasma were more precise (i.e., lower RSD) than serum, and thus we recommend plasma as the preferred matrix for this analytical method. In order to facilitate comparison of current and future plasma-based studies to previous serum-based studies, we characterized the relationships between hormone measurements in matched plasma and serum, and found that measurements across matrices are significantly and positively correlated. Lastly, to demonstrate potential applications of this method, we examined how steroid hormone profiles vary by pregnancy, sexual maturity, and stress status - pregnancy was associated with elevated progesterone, adult males had higher testosterone, and capture stress was associated with elevated corticosteroids. Overall, we conclude that this method will enable investigators to more thoroughly and efficiently evaluate steroid hormone homeostasis in bottlenose dolphins compared to immunoassay methods. These methods can potentially be applied to the assessment of sexual maturity/seasonality, pregnancy status, and stress in free-ranging bottlenose dolphins as well as those maintained under human care, and potentially other marine mammals.
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Affiliation(s)
- Thomas M Galligan
- Medical University of South Carolina, College of Graduate Studies, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, USA; JHT, Inc. Under Contract to National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, USA.
| | - Lori H Schwacke
- National Marine Mammal Foundation, 2240 Shelter Island Drive Suite 200, San Diego, CA 92106, USA.
| | - Dorian S Houser
- National Marine Mammal Foundation, 2240 Shelter Island Drive Suite 200, San Diego, CA 92106, USA.
| | - Randall S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA.
| | - Teri Rowles
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, 1315 East-West Highway, Silver Spring, MD 20910, USA.
| | - Ashley S P Boggs
- National Institute of Standards and Technology, Chemical Sciences Division, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, USA.
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9
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Mosca A, Paleari R. Sources and performance criteria of uncertainty of reference measurement procedures. Clin Biochem 2018; 57:29-36. [PMID: 29856964 DOI: 10.1016/j.clinbiochem.2018.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/09/2018] [Accepted: 05/28/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This article wants to focus on the today available Reference Measurement Procedures (RMPs) for the determination of various analytes in Laboratory Medicine and the possible tools to evaluate their performance in the laboratories who are currently using them. METHODS A brief review on the RMPs has been performed by investigating the Joint Committee for Traceability in Laboratory Medicine (JCTLM) database. In order to evaluate their performances, we have checked the organization of three international ring trials, i.e. those regularly performed by the IFCC External Quality assessment scheme for Reference Laboratories in Laboratory Medicine (RELA), by the Center for Disease Control and Prevention (CDC) cholesterol network and by the IFCC Network for HbA1c. RESULTS Several RMPs are available through the JCTLM database, but the best way to collect information about the RMPs and their uncertainties is to look at the reference measurement service providers (RMS). This part of the database and the background on how to listed in the database is very helpful for the assessment of expanded uncertainty (MU) and performance in general of RMPs. Worldwide, 17 RMS are listed in the database, and for most of the measurands more than one RMS is able to run the relative RMPs, with similar expanded uncertainties. As an example, for a-amylase, 4 SP offer their services with MU between 1.6 and 3.3%. In other cases (such as total cholesterol, the U may span over a broader range, i.e. from 0.02 to 3.6%). With regard to the performance evaluation, the approach is often heterogenous, and it is difficult to compare the performance of laboratories running the same RMP for the same measurand if involved in more than one EQAS. CONCLUSIONS The reference measurement services have been created to help laboratory professionals and manufacturers to implement the correct metrological traceability, and the JCTLM database is the only correct way to retrieve all the necessary important information to this end.
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Affiliation(s)
- Andrea Mosca
- Centre for Metrological Traceability in Laboratory Medicine (CIRME), Dept. of Physiopatholgy and Transplantation, Università degli Studi di Milano, Milano, Italy.
| | - Renata Paleari
- Centre for Metrological Traceability in Laboratory Medicine (CIRME), Dept. of Physiopatholgy and Transplantation, Università degli Studi di Milano, Milano, Italy
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10
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Boggs ASP, Schock TB, Schwacke LH, Galligan TM, Morey JS, McFee WE, Kucklick JR. Rapid and reliable steroid hormone profiling in Tursiops truncatus blubber using liquid chromatography tandem mass spectrometry (LC-MS/MS). Anal Bioanal Chem 2017. [PMID: 28631158 DOI: 10.1007/s00216-017-0446-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Monitoring of marine mammal steroid hormone status using matrices alternative to blood is desirable due to the ability to remotely collect samples, which minimizes stress to the animal. However, measurement techniques in alternative matrices such as blubber described to date are limited in the number and types of hormones measured. Therefore, a new method using bead homogenization to QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction, C18 post extraction cleanup and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to the measurement of hormone suites in bottlenose dolphin blubber. Validations were conducted in blubber from fresh dead stranded bottlenose dolphin. The final method consisting of two LC separations and garnet bead homogenization was tested for extraction efficiencies. Steroids were separated using a biphenyl column for reproductive hormones and C18 column for corticosteroids. Three hormones previously noted in blubber, testosterone, progesterone, and cortisol, were quantified in addition to previously unmeasured androstenedione, 17-hydroxyprogesterone, 11-deoxycortisol, 11-deoxycorticosterone, and cortisone in a single sample (0.4 g blubber). Extraction efficiencies of all hormones from blubber ranged from 84% to 112% and all RSDs were comparable to those reported using immunoassay methods (< 15%). The method was successfully applied to remote biopsied blubber samples to measure baseline hormone concentrations. Through this method, increased coverage of steroid hormone pathways from a single remotely collected sample potentially enhances the ability to interpret biological phenomena such as reproduction and stress in wild dolphin populations. Graphical abstract The steroid hormone profile is quantifiable from a single sample of bottlenose dolphin blubber using liquid chromatography tandem mass spectrometry. This profile can be applied to remotely collected dart biopsies and be used to determine reproductive or stress status of a wild-living dolphin.
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Affiliation(s)
- Ashley S P Boggs
- National Institute of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC, 29412, USA.
| | - Tracey B Schock
- National Institute of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC, 29412, USA
| | - Lori H Schwacke
- National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, 219 Fort Johnson Rd, Charleston, SC, 29412, USA.,National Marine Mammal Foundation, Charleston, SC, 29412, USA
| | - Thomas M Galligan
- College of Graduate Studies, Medical University of South Carolina, 68 President Street, Charleston, SC, 29425, USA.,JHT, Inc. under contract to National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC, 29412, USA
| | - Jeanine S Morey
- JHT, Inc. under contract to National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC, 29412, USA
| | - Wayne E McFee
- National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, 219 Fort Johnson Rd, Charleston, SC, 29412, USA
| | - John R Kucklick
- National Institute of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC, 29412, USA
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11
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El-Farhan N, Rees DA, Evans C. Measuring cortisol in serum, urine and saliva - are our assays good enough? Ann Clin Biochem 2017; 54:308-322. [PMID: 28068807 DOI: 10.1177/0004563216687335] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cortisol is a steroid hormone produced in response to stress. It is essential for maintaining health and wellbeing and leads to significant morbidity when deficient or present in excess. It is lipophilic and is transported bound to cortisol-binding globulin (CBG) and albumin; a small fraction (∼10%) of total serum cortisol is unbound and biologically active. Serum cortisol assays measure total cortisol and their results can be misleading in patients with altered serum protein concentrations. Automated immunoassays are used to measure cortisol but lack specificity and show significant inter-assay differences. Liquid chromatography - tandem mass spectrometry (LC-MS/MS) offers improved specificity and sensitivity; however, cortisol cut-offs used in the short Synacthen and Dexamethasone suppression tests are yet to be validated for these assays. Urine free cortisol is used to screen for Cushing's syndrome. Unbound cortisol is excreted unchanged in the urine and 24-h urine free cortisol correlates well with mean serum-free cortisol in conditions of cortisol excess. Urine free cortisol is measured predominantly by immunoassay or LC-MS/MS. Salivary cortisol also reflects changes in unbound serum cortisol and offers a reliable alternative to measuring free cortisol in serum. LC-MS/MS is the method of choice for measuring salivary cortisol; however, its use is limited by the lack of a single, validated reference range and poorly standardized assays. This review examines the methods available for measuring cortisol in serum, urine and saliva, explores cortisol in disease and considers the difficulties of measuring cortisol in acutely unwell patients and in neonates.
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Affiliation(s)
- Nadia El-Farhan
- 1 Biochemistry Department, Royal Gwent Hospital, Newport, UK
| | - D Aled Rees
- 2 Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - Carol Evans
- 3 Department of Medical Biochemistry and Immunology, University Hospital of Wales, Cardiff, UK
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12
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13
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Hawley JM, Keevil BG. Endogenous glucocorticoid analysis by liquid chromatography-tandem mass spectrometry in routine clinical laboratories. J Steroid Biochem Mol Biol 2016; 162:27-40. [PMID: 27208627 DOI: 10.1016/j.jsbmb.2016.05.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 02/07/2023]
Abstract
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful analytical technique that offers exceptional selectivity and sensitivity. Used optimally, LC-MS/MS provides accurate and precise results for a wide range of analytes at concentrations that are difficult to quantitate with other methodologies. Its implementation into routine clinical biochemistry laboratories has revolutionised our ability to analyse small molecules such as glucocorticoids. Whereas immunoassays can suffer from matrix effects and cross-reactivity due to interactions with structural analogues, the selectivity offered by LC-MS/MS has largely overcome these limitations. As many clinical guidelines are now beginning to acknowledge the importance of the methodology used to provide results, the advantages associated with LC-MS/MS are gaining wider recognition. With their integral role in both the diagnosis and management of hypo- and hyperadrenal disorders, coupled with their widespread pharmacological use, the accurate measurement of glucocorticoids is fundamental to effective patient care. Here, we provide an up-to-date review of the LC-MS/MS techniques used to successfully measure endogenous glucocorticoids, particular reference is made to serum, urine and salivary cortisol.
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Affiliation(s)
| | - Brian G Keevil
- University Hospital South Manchester, Manchester, UK; Manchester Healthcare Academy, Manchester, UK
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Development of a multi-class steroid hormone screening method using Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS). Anal Bioanal Chem 2016; 408:4179-90. [PMID: 27039201 DOI: 10.1007/s00216-016-9512-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/16/2016] [Accepted: 03/22/2016] [Indexed: 01/15/2023]
Abstract
Monitoring complex endocrine pathways is often limited by indirect measurement or measurement of a single hormone class per analysis. There is a burgeoning need to develop specific direct-detection methods capable of providing simultaneous measurement of biologically relevant concentrations of multiple classes of hormones (estrogens, androgens, progestogens, and corticosteroids). The objectives of this study were to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for multi-class steroid hormone detection using biologically relevant concentrations, then test limits of detection (LOD) in a high-background matrix by spiking charcoal-stripped fetal bovine serum (FBS) extract. Accuracy was tested with National Institute of Standards and Technology Standard Reference Materials (SRMs) with certified concentrations of cortisol, testosterone, and progesterone. 11-Deoxycorticosterone, 11-deoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, adrenosterone, androstenedione, cortisol, corticosterone, dehydroepiandrosterone, dihydrotestosterone, estradiol, estriol, estrone, equilin, pregnenolone, progesterone, and testosterone were also measured using isotopic dilution. Dansyl chloride (DC) derivatization was investigated maintaining the same method to improve and expedite estrogen analysis. Biologically relevant LODs were determined for 15 hormones. DC derivatization improved estrogen response two- to eight-fold, and improved chromatographic separation. All measurements had an accuracy ≤14 % difference from certified values (not accounting for uncertainty) and relative standard deviation ≤14 %. This method chromatographically separated and quantified biologically relevant concentrations of four hormone classes using highly specific fragmentation patterns and measured certified values of hormones that were previously split into three separate chromatographic methods.
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Hawley JM, Owen LJ, MacKenzie F, Mussell C, Cowen S, Keevil BG. Candidate Reference Measurement Procedure for the Quantification of Total Serum Cortisol with LC-MS/MS. Clin Chem 2016; 62:262-9. [DOI: 10.1373/clinchem.2015.243576] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/10/2015] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
Accurate measurement of serum cortisol is required to diagnose and treat adrenal disorders. Although certified reference materials (CRMs) are available to standardize cortisol measurements, External Quality Assessment (EQA) schemes still demonstrate a wide dispersion of results. We present a serum cortisol candidate reference measurement procedure that, through analysis of a Joint Committee for Traceability in Laboratory Medicine–listed panel of higher-order CRMs, provides metrologically traceable results.
METHOD
Isotope-labeled internal standard was added to samples before supported liquid extraction. Extracts were analyzed with LC-MS/MS in positive electrospray ionization mode. Multiple reaction monitoring was used to detect cortisol and its corresponding internal standard transitions. We measured samples in triplicate over 3 days and calculated the mean result.
RESULTS
Mean intra- and interassay imprecision were 1.3% and 1.5%, respectively, for concentrations of 154, 510, and 769 nmol/L. Ionization efficiency studies and structural analog analysis proved the method to be robust against interferences. Through analysis of 34 CRMs (83–764 nmol/L), expanded measurement uncertainty was calculated to be 5% (95% CI). The mean bias between the measured and target CRM concentrations was statistically insignificant at −0.08%.
CONCLUSIONS
The accuracy and low measurement uncertainty of this method qualify it as a CRM procedure. Metrological traceability has been achieved through the analysis of higher-order CRMs. This method could be used to underpin serum cortisol EQA schemes to provide samples with a traceable target value, enabling participating laboratories to determine the accuracy and measurement uncertainty of their assays.
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Affiliation(s)
| | - Laura J Owen
- University Hospital South Manchester, Manchester, UK
- Manchester Academic Health Science Centre, Manchester, UK
| | - Finlay MacKenzie
- Birmingham Quality, UK National External Quality Assessment Scheme, University Hospitals Birmingham National Health Service Foundation Trust, Birmingham, UK
| | | | | | - Brian G Keevil
- University Hospital South Manchester, Manchester, UK
- Manchester Academic Health Science Centre, Manchester, UK
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Smajdor J, Piech R, Rumin M, Bator BP. New high sensitive hydrocortisone determination by means of adsorptive stripping voltammetry on renewable mercury film silver based electrode. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.09.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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17
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Tai SSC, Nelson MA. Candidate Reference Measurement Procedure for the Determination of (24R),25-Dihydroxyvitamin D3 in Human Serum Using Isotope-Dilution Liquid Chromatography-Tandem Mass Spectrometry. Anal Chem 2015; 87:7964-70. [PMID: 26171884 DOI: 10.1021/acs.analchem.5b01861] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The two major forms of vitamin D, vitamin D3 and vitamin D2, are metabolized in the liver through hydroxylation to 25-hydroxyvitamin D species, and then further hydroxylated in the kidney to various dihydroxyvitamin D species. (24R),25-Dihydroxyvitamin D3 ((24R),25(OH)2D3) is a major catabolite of 25-hydroxyvitamin D metabolism and is an important vitamin D metabolite used as a catabolism marker and indicator of kidney disease. The National Institute of Standards and Technology has recently developed a reference measurement procedure for the determination of (24R),25(OH)2D3 in human serum using isotope-dilution LC-MS/MS. The (24R),25(OH)2D3 and added deuterated labeled internal standard (24R),25(OH)2D3-d6 were extracted from serum matrix using liquid-liquid extraction prior to LC-MS/MS analysis. Chromatographic separation was performed using a fused-core C18 column. Atmospheric pressure chemical ionization in the positive ion mode and multiple reaction monitoring were used for LC-MS/MS. The accuracy of the measurement of (24R),25(OH)2D3 was evaluated by recovery studies of measuring (24R),25(OH)2D3 in gravimetrically prepared spiked samples of human serum with known (24R),25(OH)2D3 levels. The recoveries of the added (24R),25(OH)2D3 averaged 99.0% (0.8% SD), and the extraction efficiencies averaged 95% (2% SD). Excellent repeatability was demonstrated with CVs of ∼1%. The limit of quantitation at a signal-to-noise ratio of ∼10 was 0.2 ng/g. Potential isomeric interferences from other endogenous species and from impurity components of the reference standard were investigated. LC baseline resolution of (24R),25(OH)2D3 from these isomers was achieved within 35 min. This method was used for value assignment of (24R),25(OH)2D3 in Standard Reference Materials of Vitamin D Metabolites in Human Serum, which can serve as an accuracy base for routine methods used in clinical laboratories.
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Affiliation(s)
- Susan S-C Tai
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Michael A Nelson
- Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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18
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Quinete N, Bertram J, Reska M, Lang J, Kraus T. Highly selective and automated online SPE LC–MS 3 method for determination of cortisol and cortisone in human hair as biomarker for stress related diseases. Talanta 2015; 134:310-316. [DOI: 10.1016/j.talanta.2014.11.034] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/07/2014] [Accepted: 11/17/2014] [Indexed: 11/16/2022]
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Kawaguchi M, Eyama S, Takatsu A. Automated isotope dilution liquid chromatography–tandem mass spectrometry with on-line dilution and solid phase extraction for the measurement of cortisol in human serum sample. J Pharm Biomed Anal 2014; 96:220-3. [DOI: 10.1016/j.jpba.2014.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/07/2014] [Accepted: 03/10/2014] [Indexed: 11/24/2022]
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20
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Bravery CA, French A. Reference materials for cellular therapeutics. Cytotherapy 2014; 16:1187-96. [PMID: 25065634 DOI: 10.1016/j.jcyt.2014.05.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/26/2014] [Accepted: 05/30/2014] [Indexed: 01/01/2023]
Abstract
The development of cellular therapeutics (CTP) takes place over many years, and, where successful, the developer will anticipate the product to be in clinical use for decades. Successful demonstration of manufacturing and quality consistency is dependent on the use of complex analytical methods; thus, the risk of process and method drift over time is high. The use of reference materials (RM) is an established scientific principle and as such also a regulatory requirement. The various uses of RM in the context of CTP manufacturing and quality are discussed, along with why they are needed for living cell products and the analytical methods applied to them. Relatively few consensus RM exist that are suitable for even common methods used by CTP developers, such as flow cytometry. Others have also identified this need and made proposals; however, great care will be needed to ensure any consensus RM that result are fit for purpose. Such consensus RM probably will need to be applied to specific standardized methods, and the idea that a single RM can have wide applicability is challenged. Written standards, including standardized methods, together with appropriate measurement RM are probably the most appropriate way to define specific starting cell types. The characteristics of a specific CTP will to some degree deviate from those of the starting cells; consequently, a product RM remains the best solution where feasible. Each CTP developer must consider how and what types of RM should be used to ensure the reliability of their own analytical measurements.
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Affiliation(s)
- Christopher A Bravery
- Consulting on Advanced Biologicals Ltd. Advanced Biologicals Ltd, London, United Kingdom.
| | - Anna French
- The Oxford-UCL Centre for the Advancement of Sustainable Medical Innovation (CASMI), The University of Oxford, Oxford, United Kingdoms
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21
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Abstract
Cortisol is quantitatively the major glucocorticoid product of the adrenal cortex. The main reason to measure cortisol is to diagnose human diseases characterised by deficiency of adrenal steroid excretion in Addison's disease or overproduction in Cushing's syndrome (CS). In both cases a sensitive, accurate and reproducible assay of cortisol is required. Several methods have been described for the quantitative measurement of cortisol in both serum and urine. The most widely used methods in routine clinical laboratories are immunoassays (IA) and enzyme immunoassays (EIA), luminescence and fluorescence assays, which are available in numerous commercial kits and on automated platforms. However, there remains a number of problems in the so-called direct immunoassays if extraction and prepurification are not carried out before the assay. Recently, more specific chromatographic methods have been introduced, such as high pressure liquid chromatographic (HPLC) or liquid chromatography tandem mass spectrometric assays (LC-MS/MS). The high specificity especially of LC-MS/MS facilitates reliable measurement of cortisol both in plasma, urine and saliva samples.
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Affiliation(s)
- Ursula Turpeinen
- HUSLAB, Laboratory of Women's Clinic, Haartmaninkatu 2, 00290 Helsinki, Finland.
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22
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El-Farhan N, Pickett A, Ducroq D, Bailey C, Mitchem K, Morgan N, Armston A, Jones L, Evans C, Rees DA. Method-specific serum cortisol responses to the adrenocorticotrophin test: comparison of gas chromatography-mass spectrometry and five automated immunoassays. Clin Endocrinol (Oxf) 2013; 78:673-80. [PMID: 22994849 DOI: 10.1111/cen.12039] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/02/2012] [Accepted: 09/05/2012] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The serum cortisol response to the adrenocorticotrophin (ACTH) test is known to vary significantly by assay, but lower reference limits (LRL) for this response have not been established by the reference gas chromatography-mass spectrometry (GC-MS) method or modern immunoassays. We aimed to compare the normal cortisol response to ACTH stimulation using GC-MS with five widely used immunoassays. DESIGN, PATIENTS AND MEASUREMENTS An ACTH test (250 μg iv ACTH1-24 ) was undertaken in 165 healthy volunteers (age, 20-66 years; 105 women, 24 of whom were taking an oestrogen-containing oral contraceptive pill [OCP]). Serum cortisol was measured using GC-MS, Advia Centaur (Siemens), Architect (Abbott), Modular Analytics E170 (Roche), Immulite 2000 (Siemens) and Access (Beckman) automated immunoassays. The estimated LRL for the 30 min cortisol response to ACTH was derived from the 2·5th percentile of log-transformed concentrations. RESULTS The GC-MS-measured cortisol response was normally distributed in males but not females, with no significant gender difference in baseline or post-ACTH cortisol concentration. Immunoassays were positively biased relative to GC-MS, except in samples from women on the OCP, who showed a consistent negative bias. The LRL for cortisol was method-specific [GC-MS: 420 nm; Architect: 430 nm; Centaur: 446 nm; Access 459 nm; Immulite (2000) 474 nm] and, for the E170, also gender-specific (female: 524 nm; male 574 nm). A separate LRL is necessary for women on the OCP. CONCLUSIONS Normal cortisol responses to the ACTH test are influenced significantly by assay and oestrogen treatment. We recommend the use of separate reference limits in premenopausal women on the OCP and warn users that cortisol measurements in this subgroup are subject to assay interference.
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Affiliation(s)
- Nadia El-Farhan
- Department of Medical Biochemistry and Immunology, University Hospital of Wales, Cardiff, UK
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23
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Abstract
Mass spectrometry methods have the potential to measure different hormones during the same analysis and have improved specificity and a wide analytical range compared with many immunoassay methods. Increasingly in clinical laboratories liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays are replacing immunoassays for the routine measurement of testosterone, 17-hydroxyprogesterone, and other steroid hormones. Reference LC-MS/MS methods for steroid, thyroid, and peptide hormones are being used for assessment of the performance and calibration of commercial immunoassays. In this chapter, the general principles of tandem mass spectrometry and examples of hormone assays are described.
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Affiliation(s)
- Helen P Field
- Department of Specialist Laboratory Medicine, St. James's University Hospital, Leeds, UK
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24
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Chen Y, Liu Q, Yong S, Lee TK. High accuracy analysis of glucose in human serum by isotope dilution liquid chromatography-tandem mass spectrometry. Clin Chim Acta 2012; 413:808-13. [DOI: 10.1016/j.cca.2012.01.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 01/20/2012] [Accepted: 01/23/2012] [Indexed: 11/30/2022]
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25
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The coming of age of liquid chromatography coupled to tandem mass spectrometry in the endocrinology laboratory. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 883-884:50-8. [DOI: 10.1016/j.jchromb.2011.08.027] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 08/19/2011] [Indexed: 02/07/2023]
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26
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Abstract
Quantification of endogenous hormonal steroids and their precursors is essential for diagnosing a wide range of endocrine disorders. Historically, these analyses have been carried out using immunoassay, but such methods are problematic, especially for low-concentration analytes, due to assay interference by other endogenous steroids. MS offers improved specificity over immunoassay and can be highly sensitive. GC–MS, with use of stable isotopically labeled internal standards, is considered the ‘gold standard’ method for serum steroid analysis. GC–MS is the method of choice for profiling steroid metabolites in urine, but these techniques are not appropriate for routine use in clinical laboratories owing to a need for extensive sample preparation, as well as analytical expertise. LC–MS/MS compares well to GC–MS in terms of accuracy, precision and sensitivity, but allows simplified sample preparation. While most publications have featured only one or a limited number of steroids, we consider that steroid paneling (which we propose as the preferred term for multitargeted steroid analysis) has great potential to enable clinicians to make a definitive diagnosis. It is adaptable for use in a number of matrices, including serum, saliva and dried blood spots. However, LC–MS/MS-based steroid analysis is not straightforward, and understanding the chemical and analytical processes involved is essential for implementation of a robust clinical service. This article discusses specific challenges in the measurement of endogenous steroids using LC–MS/MS, and provides examples of the benefits it offers.
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Ruiter AFC, Teeninga N, Nauta J, Endert E, Ackermans MT. Determination of unbound prednisolone, prednisone and cortisol in human serum and saliva by on-line solid-phase extraction liquid chromatography tandem mass spectrometry and potential implications for drug monitoring of prednisolone and prednisone in sali. Biomed Chromatogr 2011; 26:789-96. [DOI: 10.1002/bmc.1730] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 09/09/2011] [Indexed: 11/09/2022]
Affiliation(s)
- A. F. C. Ruiter
- Department of Clinical Chemistry; Laboratory of Endocrinology; Academic Medical Center; Amsterdam; The Netherlands
| | - N. Teeninga
- Department of Pediatrics; Erasmus Medical Center-Sophia Children's Hospital; Rotterdam; The Netherlands
| | - J. Nauta
- Department of Pediatrics; Erasmus Medical Center-Sophia Children's Hospital; Rotterdam; The Netherlands
| | - E. Endert
- Department of Clinical Chemistry; Laboratory of Endocrinology; Academic Medical Center; Amsterdam; The Netherlands
| | - M. T. Ackermans
- Department of Clinical Chemistry; Laboratory of Endocrinology; Academic Medical Center; Amsterdam; The Netherlands
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28
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Arya SK, Dey A, Bhansali S. Polyaniline protected gold nanoparticles based mediator and label free electrochemical cortisol biosensor. Biosens Bioelectron 2011; 28:166-73. [DOI: 10.1016/j.bios.2011.07.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/06/2011] [Accepted: 07/08/2011] [Indexed: 10/17/2022]
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29
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Development and validation of a reference measurement procedure for certification of phenytoin, phenobarbital, lamotrigine, and topiramate in human serum using isotope-dilution liquid chromatography/tandem mass spectrometry. Anal Bioanal Chem 2011; 401:1915-22. [DOI: 10.1007/s00216-011-5251-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/15/2011] [Accepted: 07/13/2011] [Indexed: 11/26/2022]
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30
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Monaghan PJ, Owen LJ, Trainer PJ, Brabant G, Keevil BG, Darby D. Comparison of serum cortisol measurement by immunoassay and liquid chromatography-tandem mass spectrometry in patients receiving the 11 -hydroxylase inhibitor metyrapone. Ann Clin Biochem 2011; 48:441-6. [DOI: 10.1258/acb.2011.011014] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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31
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Determination of cortisol production rates with contemporary liquid chromatography-mass spectrometry to measure cortisol-d(3) dilution after infusion of deuterated tracer. Clin Biochem 2010; 44:430-4. [PMID: 21185275 DOI: 10.1016/j.clinbiochem.2010.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 12/15/2010] [Accepted: 12/16/2010] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Measurement of 24-h cortisol production rate (CPR) using steady-state infusion of deuterated cortisol and analysis of stable-isotope dilution by MS is a valuable tool to examine hypothalamic-pituitary-adrenal axis activity in humans. We have developed and validated an improved method for measuring cortisol dilution with contemporary LC-MS technology. DESIGN AND METHODS Plasma samples and calibrators were extracted with ethylacetate. LC-MS was performed with a Surveyor HPLC and TSQ Quantum triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) source. RESULTS Selectivity was improved over previous methods via elimination of an interferent identified as 20β-dihydrocortisol. The LLOQ for cortisol-d(3) was 2.73nmol/L and LOD 1.37nmol/L. Plasma calibrators were linear over the concentration range 1.5-10% cortisol-d(3), with correlation coefficients >0.995. CONCLUSIONS This APCI LC-MS method offers simplified sample work-up and analysis and enables selective detection of the low concentration of cortisol-d(3) infused for determination of 24-h CPR.
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32
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A comparison of edge- and basal-plane pyrolytic graphite electrodes towards the sensitive determination of hydrocortisone. Talanta 2010; 83:149-55. [DOI: 10.1016/j.talanta.2010.08.054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 08/26/2010] [Accepted: 08/27/2010] [Indexed: 11/21/2022]
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33
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Owen LJ, Halsall DJ, Keevil BG. Cortisol measurement in patients receiving metyrapone therapy. Ann Clin Biochem 2010; 47:573-5. [DOI: 10.1258/acb.2010.010167] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Current guidance recommends titrating the dose of metyrapone against serum cortisol concentration, in patients under medical management of Cushing's syndrome. In the UK, this almost always involves measuring serum cortisol concentration by immunoassay, the performance of which is questionable in the presence of altered steroid metabolism. Sera from two patients receiving metyrapone were analysed using a liquid chromatography tandem mass spectrometry (MS) steroid assay to identify which steroids, if any, were elevated in these patients. In addition, control serum was spiked with a series of steroids to identify any potential positive interferences in a cortisol immunoassay. Serum 11-deoxycortisol concentration was elevated in both of the patients studied. One patient also had an elevated serum 17-hydroxyprogesterone concentration and the other an elevated androstenedione. In addition, the results of the interference studies indicated that the cortisol immunoassay was susceptible to interference from 11-deoxycortisol, 17-hydroxyprogesterone and 21-deoxycortisol. However, the magnitude of interference, in the serum cortisol immunoassay, due to these three steroids could not account for the discrepancy between the cortisol concentrations measured by immunoassay and those measured by MS. Both clinicians and laboratory staff should be aware of these interferences when monitoring patients undergoing treatment with metyrapone, and consequently serum should be measured in these patients by MS, not by immunoassay.
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Affiliation(s)
- L J Owen
- Biochemistry Department, University Hospital of South Manchester, Manchester M23 9LT
| | - D J Halsall
- Clinical Biochemistry Department, Addenbrooke's Hospital, Cambridge, UK
| | - B G Keevil
- Biochemistry Department, University Hospital of South Manchester, Manchester M23 9LT
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34
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Chen LQ, Kang XJ, Sun J, Deng JJ, Gu ZZ, Lu ZH. Application of nanofiber-packed SPE for determination of salivary-free cortisol using fluorescence precolumn derivatization and HPLC detection. J Sep Sci 2010; 33:2369-75. [DOI: 10.1002/jssc.201000071] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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35
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Arya SK, Chornokur G, Venugopal M, Bhansali S. Dithiobis(succinimidyl propionate) modified gold microarray electrode based electrochemical immunosensor for ultrasensitive detection of cortisol. Biosens Bioelectron 2010; 25:2296-301. [PMID: 20382518 PMCID: PMC2869627 DOI: 10.1016/j.bios.2010.03.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 03/09/2010] [Accepted: 03/10/2010] [Indexed: 01/24/2023]
Abstract
Gold microelectrode arrays functionalized with dithiobis(succinimidyl propionate) self-assembled monolayer (SAM) have been used to fabricate an ultrasensitive, disposable, electrochemical cortisol immunosensor. Cortisol specific monoclonal antibody (C-Mab) was covalently immobilized on the surface of gold microelectrode array and the sensors were exposed to solutions with different cortisol concentration. After C-Mab binding, unreacted active groups of DTSP were blocked using ethanol amine (EA) and label-free electrochemical impedance (EIS) technique was used to determine cortisol concentration. EIS results confirmed that EA/C-Mab/DTSP/Au based biosensor can accurately detect cortisol in the range of 1pM-100nM. The biosensor was successfully used for the measurement of cortisol in interstitial fluid in vitro. This research establishes the feasibility of using impedance based biosensor architecture for disposable, wearable cortisol detector.
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Affiliation(s)
- Sunil K. Arya
- Bio-MEMS and Microsystem Lab, Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, United States
| | - Ganna Chornokur
- Bio-MEMS and Microsystem Lab, Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, United States
| | - Manju Venugopal
- Guided Therapeutics Inc. 5835 Peachtree Corners East, Suite D, Norcross, GA 30092
| | - Shekhar Bhansali
- Bio-MEMS and Microsystem Lab, Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, United States
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36
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Tai SSC, Bedner M, Phinney KW. Development of a candidate reference measurement procedure for the determination of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in human serum using isotope-dilution liquid chromatography-tandem mass spectrometry. Anal Chem 2010; 82:1942-8. [PMID: 20136128 DOI: 10.1021/ac9026862] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Vitamin D exists in two major forms, vitamin D(3) and vitamin D(2). Vitamin D helps the body absorb calcium and promote optimal bone health. Both forms of vitamin D are metabolized to 25-hydroxyvitamin D in the body, and the levels of 25-hydroxyvitamin D(3) [25(OH)D(3)] and 25-hydroxyvitamin D(2) [25(OH)D(2)] in serum are considered the best indicators of vitamin D status. A candidate reference measurement procedure for serum 25(OH)D(3) and 25(OH)D(2) has been developed and critically evaluated. The deuterated compounds 25(OH)D(3)-d(3) and 25(OH)D(2)-d(3) are used as internal standards for 25(OH)D(3) and 25(OH)D(2), respectively. The 25(OH)D(3) and 25(OH)D(2) and their respective labeled internal standards are simultaneously extracted from serum using liquid-liquid extraction prior to reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chromatographic separation was performed using a cyano (CN) column for both 25(OH)D(3) and 25(OH)D(2). Atmospheric pressure chemical ionization (APCI) in the positive ion mode and multiple reaction monitoring (MRM) were used for LC-MS/MS. The accuracy of the method was evaluated by recovery studies of measuring 25-hydroxyvitamin D [25(OH)D] in spiked samples with known 25(OH)D levels. The recoveries of the added 25(OH)D(3) and 25(OH)D(2) ranged from 99.0% to 101.0%. The absolute recoveries with this method were 97% and 92% for 25(OH)D(3) and 25(OH)D(2), respectively. Excellent precision was obtained with between-set coefficients of variation (CVs) of 0.2-0.6% for 25(OH)D levels >1 ng/g and within 2% for the level of <1 ng/g. Chromatographic separation of 25(OH)D(3) and 25(OH)D(2) from their respective isomers 3-epi-25(OH)D(3) and 3-epi-25(OH)D(2) was achieved. The limit of detection at a signal-to-noise ratio of approximately 3 was 40 pg of 25(OH)D on column (or approximately 0.15 ng/g as expressed as a concentration). This candidate reference measurement procedure for serum 25(OH)D(3) and 25(OH)D(2) demonstrates good accuracy and precision and low susceptibility to interferences. It can be used to provide an accuracy base to which clinical methods for 25(OH)D(3) and 25(OH)D(2) can be compared and that will serve as a standard of higher order for measurement traceability.
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Affiliation(s)
- Susan S-C Tai
- Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8392, USA.
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Lee HS, Shin HS, Park SR, Park CJ. Measurement of Cortisol in Human Serum by Isotope Dilution Liquid Chromatography/Mass Spectrometry and a Comparison through a Proficiency Testing. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.5.1149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Owen LJ, Haslam S, Adaway JE, Wood P, Glenn C, Keevil BG. A simplified liquid chromatography tandem mass spectrometry assay, using on-line solid-phase extraction, for the quantitation of cortisol in saliva and comparison with a routine DELFIA method. Ann Clin Biochem 2010; 47:131-6. [DOI: 10.1258/acb.2009.009053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background We have developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for measuring salivary cortisol, which requires only 200 μL sample and no extraction. Methods Sample (200 μL) and 25 μL internal standard were added directly to a 96-deep-well plate. Of this, 50 μL was loaded onto a guard cartridge, the cartridge was then washed and the eluate was diverted to waste. The compounds were eluted from the guard cartridge onto the C18 analytical column. Cortisol and deuterated cortisol were monitored using transitions m/z 363.2 > 121.1 and 365.1 > 122.2, respectively. Results The method had a lower limit of quantitation of 2 nmol/L. Intra-assay and inter-assay imprecision were better than 9.5%. Comparison with an established dissociation enhanced lanthanide fluorescent immunoassay (DELFIA) gave good agreement for the majority of samples; LC-MS/MS = 1.0065 × DELFIA − 3.7 ( n = 130). The reference range was determined to be 5.8–45.7 nmol/L at 08:00 h and <6.4 nmol/L at 23:00 h ( n = 44). Conclusions We have developed a simple, robust assay to measure salivary cortisol using on-line solid-phase extraction to reduce sample clean-up requirements.
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Affiliation(s)
- L J Owen
- Department of Clinical Biochemistry, University Hospital of South Manchester, Southmoor Road, Manchester M23 9LT
| | - S Haslam
- Department of Clinical Biochemistry, University Hospital of South Manchester, Southmoor Road, Manchester M23 9LT
| | - J E Adaway
- Department of Clinical Biochemistry, University Hospital of South Manchester, Southmoor Road, Manchester M23 9LT
| | - P Wood
- Endocrine Unit, Department of Chemical Pathology, Southampton University Hospital, Tremona Road, Southampton SO16 6YD, UK
| | - C Glenn
- Endocrine Unit, Department of Chemical Pathology, Southampton University Hospital, Tremona Road, Southampton SO16 6YD, UK
| | - B G Keevil
- Department of Clinical Biochemistry, University Hospital of South Manchester, Southmoor Road, Manchester M23 9LT
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Antibody modified gold micro array electrode based electrochemical immunosensor for ultrasensitive detection of cortisol in saliva and ISF. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.proeng.2010.09.230] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Brun V, Masselon C, Garin J, Dupuis A. Isotope dilution strategies for absolute quantitative proteomics. J Proteomics 2009; 72:740-9. [DOI: 10.1016/j.jprot.2009.03.007] [Citation(s) in RCA: 217] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 03/05/2009] [Accepted: 03/24/2009] [Indexed: 10/20/2022]
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Ionita IA, Fast DM, Akhlaghi F. Development of a sensitive and selective method for the quantitative analysis of cortisol, cortisone, prednisolone and prednisone in human plasma. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:765-72. [PMID: 19237320 DOI: 10.1016/j.jchromb.2009.02.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/05/2009] [Accepted: 02/06/2009] [Indexed: 11/30/2022]
Abstract
A highly selective, sensitive and robust LC-MS/MS method was developed for the simultaneous quantification of cortisol, cortisone, prednisolone and prednisone in human plasma. Prednisolone, cortisol and cortisone have similar fragmentation pattern. These three compounds were chromatographically separated, thus eliminating the inherent interference that fragments derived from the M+2 and M isotopes of prednisolone contribute in the MRM channels of cortisol and cortisone, respectively. Additionally, by using a small particle (1.8 microm) analytical column, interferences present in the plasma samples from post-transplant recipients were successfully resolved from cortisol after a simple extraction consisting of protein precipitation, evaporation and reconstitution. The chromatographic separation was achieved on a Zorbax-SB Phenyl column under isocratic conditions during a run time of 8 min. Intra-run and inter-run precision and accuracy within +/-15% were achieved during a 3-run validation for quality control samples at five concentration levels in charcoal-stripped plasma as well as in normal plasma, over a 500-fold dynamic concentration range. The lower limit of quantitation was 0.500 ng/mL for cortisone and prednisone, 1.00 ng/mL for cortisol and 2.00 ng/mL for prednisolone. The performance of the small particle column was maintained during more than 1200 injections in terms of peak retention time, symmetry and backpressure.
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Affiliation(s)
- Ileana A Ionita
- Department of Pharmacokinetics Dynamics and Metabolism, Pfizer Global Research and Development, Groton, CT 06340, USA
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KAWAGUCHI M, TAKATSU A. Development of a Candidate Reference Measurement Procedure for the Analysis of Cortisol in Human Serum Samples by Isotope Dilution-Gas Chromatography-Mass Spectrometry. ANAL SCI 2009; 25:989-92. [DOI: 10.2116/analsci.25.989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Veldhuis JD, Keenan DM, Pincus SM. Motivations and methods for analyzing pulsatile hormone secretion. Endocr Rev 2008; 29:823-64. [PMID: 18940916 PMCID: PMC2647703 DOI: 10.1210/er.2008-0005] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 09/16/2008] [Indexed: 01/05/2023]
Abstract
Endocrine glands communicate with remote target cells via a mixture of continuous and intermittent signal exchange. Continuous signaling allows slowly varying control, whereas intermittency permits large rapid adjustments. The control systems that mediate such homeostatic corrections operate in a species-, gender-, age-, and context-selective fashion. Significant progress has been made in understanding mechanisms of adaptive interglandular signaling in vivo. Principal goals are to understand the physiological origins, significance, and mechanisms of pulsatile hormone secretion. Key analytical issues are: 1) to quantify the number, size, shape, and uniformity of pulses, nonpulsatile (basal) secretion, and elimination kinetics; 2) to evaluate regulation of the axis as a whole; and 3) to reconstruct dose-response interactions without disrupting hormone connections. This review will focus on the motivations driving and the methodologies used for such analyses.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Department of Internal Medicine, Mayo Medical School, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Routine method for the simultaneous quantification of 17α-hydroxyprogesterone, testosterone, dehydroepiandrosterone, androstenedione, cortisol, and pregnenolone in human serum of neonates using gas chromatography–mass spectrometry. J Chromatogr A 2008; 1206:166-77. [DOI: 10.1016/j.chroma.2008.07.057] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Revised: 07/06/2008] [Accepted: 07/16/2008] [Indexed: 11/21/2022]
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Heinig K, Wirz T, Bucheli F. Determination of Glucocorticoids in Animal Plasma, Urine and Tissues by Column-Switching LC–Tandem-MS. Chromatographia 2008. [DOI: 10.1365/s10337-008-0776-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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van Gammeren AJ, van Gool N, de Groot MJM, Cobbaert CM. Analytical performance evaluation of the Cobas 6000 analyzer - special emphasis on trueness verification. Clin Chem Lab Med 2008; 46:863-71. [PMID: 18601611 DOI: 10.1515/cclm.2008.159] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Consolidation of analyzers is an emerging issue in clinical chemistry. We evaluated the analytical performance of the Cobas 6,000 analyzer (Roche Diagnostics), which is considered a candidate for replacement of current Hitachi 917 analyzers and for consolidation of chemistry and immunochemistry. METHODS The precision, accuracy, linearity and correlation with current field methods were evaluated according to Clinical and Laboratory Standards Institute protocols EP5, EP9 and EP10. A total of 31 routine chemistry assays and 18 immunoassays were studied. Accuracy and linearity were verified for 24 chemistry parameters using value-assigned trueness controls from the Dutch External Quality Assessment Scheme organizers. In addition, traceability to methods endorsed by the Joint Committee of Traceability in Laboratory Medicine was examined. RESULTS All analytes met allowable precision criteria, apart from the low level for sodium and folate. Total coefficients of variation ranged between 0.6% and 4.4% for routine chemistry and between 0.8% and 5.8% for immunochemistry, apart from folate (12% at the low end). The correlation coefficients for comparison to current field methods were >0.975, except for magnesium and for six out of 18 immunochemistries. Recovery experiments indicated high recovery for most of the 24 routine chemistry assays. CONCLUSIONS Considering the excellent precision data and the result equivalence for most assays, it can be concluded that Cobas 6,000 accommodates robust chemistry and immunochemistry, and has good potential for workstation consolidation in medium-sized laboratories.
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Affiliation(s)
- Adriaan J van Gammeren
- Department of Clinical Chemistry and Hematology, Amphia Hospital, Breda, The Netherlands.
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Liu M, Yan W, Lin JM, Hashi Y, Liu LB, Wei Y. On-line liquid chromatography–mass spectrometry with dilution line to achieve large volume urine injection for the improvement of sensitivity. J Chromatogr A 2008; 1198-1199:87-94. [DOI: 10.1016/j.chroma.2008.05.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 04/01/2008] [Accepted: 05/06/2008] [Indexed: 10/22/2022]
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Duxbury K, Owen L, Gillingwater S, Keevil B. Naturally occurring isotopes of an analyte can interfere with doubly deuterated internal standard measurement. Ann Clin Biochem 2008; 45:210-2. [DOI: 10.1258/acb.2007.007137] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background Internal standards are essential in quantitative mass spectrometry (MS) assays to correct for variability in sample extraction and ionization at the source. In liquid chromatography MS assays, analogues of the analyte with several atoms replaced by their stable isotopes, e.g. 2H (D, deuterium) are often used as internal standards. Methods Possible interference by naturally occurring isotopes of an analyte in the internal standard channel in a liquid chromatography tandem MS assay was assessed using cortisol and its deuterated internal standard, D2-cortisol, as an example. Mass spectra were analysed and standard curves were prepared with varying concentrations of internal standard to determine the extent of any interference. Results The mass spectra showed that a naturally occurring isotope of cortisol at m/z 365 acts in the same way as D2-cortisol and fragments to give a daughter ion of the same m/z. Cortisol-365 can therefore falsely, but significantly, increase the amount of internal standard detected, and this will concomitantly decrease the relative response for cortisol. The standard curves with varying concentrations of internal standard showed that this phenomenon can affect the linearity of an assay. Conclusions Our results show that care is needed in assay development when doubly deuterated internal standards are used. Interference by naturally occurring isotopes of the analyte of interest in the internal standard transition is possible and it is important to ensure that an appropriate internal standard concentration is chosen that permits linearity of the assay over the required range.
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Affiliation(s)
- K Duxbury
- University Hospital of South Manchester NHS Foundation Trust, Southmoor Road, Manchester M23 9LT, UK
| | - L Owen
- University Hospital of South Manchester NHS Foundation Trust, Southmoor Road, Manchester M23 9LT, UK
| | | | - B Keevil
- University Hospital of South Manchester NHS Foundation Trust, Southmoor Road, Manchester M23 9LT, UK
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Tai SSC, Xu B, Welch MJ, Phinney KW. Development and evaluation of a candidate reference measurement procedure for the determination of testosterone in human serum using isotope dilution liquid chromatography/tandem mass spectrometry. Anal Bioanal Chem 2007; 388:1087-94. [PMID: 17530229 DOI: 10.1007/s00216-007-1355-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 05/08/2007] [Indexed: 10/23/2022]
Abstract
A candidate reference measurement procedure for total testosterone in human serum involving isotope dilution (ID) coupled with liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. The endogenous testosterone and its internal standard (testosterone-d (3)) were extracted from the serum matrix using a combination of solid-phase extraction and liquid-liquid extraction prior to reversed-phase LC/MS/MS. Accuracy of the measurements was evaluated by a recovery study using testosterone-spiked serum. The recovery of the added testosterone ranged from 100.0 to 100.3%. This method was applied to the determination of testosterone in frozen serum samples from three individual donors (one female and two males) with the testosterone concentrations ranging from 0.3 to 8.5 ng g(-1). Repeatability with within-set coefficients of variation (CVs) from 0.1 to 1.0% and intermediate precision with between-set CVs from 0.1 to 0.5% for both female and male serum materials were demonstrated. Excellent linearity was obtained for all linear regression lines. The detection limit at a signal-to-noise ratio of approximately 3 was 2 pg of testosterone in serum. Structural analogs as well as testosterone metabolites were tested and found to not interfere with the measurement of testosterone. This well-characterized LC/MS/MS method for serum testosterone, which demonstrates good accuracy and precision, and low susceptibility to interferences, qualifies as a reference measurement procedure that can be used to provide an accuracy base to which routine methods for testosterone can be compared and that will serve as a standard of higher order for measurement traceability.
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Affiliation(s)
- Susan S-C Tai
- Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8392, USA.
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Zhang Y, Wu HL, Ding YJ, Xia AL, Cui H, Yu RQ. Simultaneous determination of cortisol and prednisolone in body fluids by using HPLC–DAD coupled with second-order calibration based on alternating trilinear decomposition. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 840:116-23. [PMID: 16714156 DOI: 10.1016/j.jchromb.2006.04.043] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 04/10/2006] [Accepted: 04/28/2006] [Indexed: 11/17/2022]
Abstract
A novel method for simultaneous determination of cortisol and prednisolone in body fluids has been developed in this paper. Three-way data recorded by high-performance liquid chromatography with a diode array detector (HPLC-DAD) have been analyzed by second-order calibration based on the alternating trilinear decomposition (ATLD) algorithm. The chemometric methodology selected exploits the second-order advantage of the three-way data arrays, which allows one to obtain concentrations of individual calibrated analytes even in the presence of interferences not present in the calibration samples (e.g. background in urine or plasma). It was applied to simultaneous determination of cortisol and prednisolone in both plasma and urine samples. Though the chromatographic and spectral peaks of the analytes were heavily overlapped and interferents coeluted with the compounds studied, good recoveries of the analytes could be obtained with HPLC-DAD coupled with second-order calibration based on ATLD. Sample preparation was based on solvent extraction (SE), and quantification can be carried out with simple mobile phase. The time required for the quantification process is shorter than other methods.
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Affiliation(s)
- Yan Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
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