Gentamicin and Vancomycin Interference on Results of Clinical Chemistry Parameters on Abbott Architect c8000

CONTEXT.—

Gentamicin and vancomycin are nephrotoxic antibiotics. Little is known about the influence of drug concentrations on results of clinical chemistry tests.

OBJECTIVE.—

To investigate gentamicin and vancomycin interference on results of 33 commonly measured biochemistry tests.

DESIGN.—

The study was carried out in the University Department of Chemistry, Medical School University Hospital Sestre Milosrdnice (Zagreb, Croatia). For each drug, 10 aliquots of pooled serum were prepared. In order to cover toxic concentrations, pool serum samples were spiked with drugs to obtain 0 to 50 μg/mL of gentamicin and 0 to 200 μg/mL of vancomycin. Biochemistry tests were measured in duplicate on the Architect c8000 analyzer, and drug concentrations were measured on Architect i2000 SR (both Abbott Laboratories, Abbott Park, Illinois). For each tested concentration, bias was calculated against the initial measurement. Acceptance criteria were defined as measurement uncertainty of the commercial control with the value close to the measured range of the pool sample.

RESULTS.—

For gentamicin, all bias values were below established criteria. For vancomycin, significant changes were observed for potassium, direct bilirubin, and immunoglobulin A. Significant bias was already detected at low vancomycin concentration (2.98 μg/mL) for direct bilirubin (bias = 9.7%; acceptable = 8%). Potassium bias at the highest vancomycin concentration (204.4 μg/mL) exceeded acceptance criteria (bias = 4.5%; acceptable = 4%). For immunoglobulin A, no apparent trend was observed, and bias is attributed to increased method imprecision.

CONCLUSIONS.—

Gentamicin did not interfere with the results of clinical chemistry tests. Direct bilirubin concentration is falsely increased in the presence of vancomycin, and potassium is affected at high concentrations.

Does recreational scuba diving have clinically significant effect on routine haematological parameters?

Introduction

Scuba diving represents a combination of exercise and changes in environmental conditions. This study aimed to evaluate changes in haematological parameters after recreational scuba diving in order to identify clinically significant changes.

Materials and methods

The study included males, 17 recreational divers, median age (range) 41 (30-52) years. Blood samples were taken before diving, immediately after diving to 30 meters for 30 minutes, 3 hours and 6 hours after diving. Complete blood counts were analyzed on the Cell Dyn Ruby haematology analyzer. Statistical significance between successive measurements was tested using Friedman test. The difference between the two measurements was judged against desirable bias (DSB) derived from biological variation and calculated reference change values (RCV). The difference higher than RCV was considered clinically significant.

Results

A statistically significant increase and difference judging against DSB was observed: for neutrophils immediately, 3 and 6 hours after diving (18%, 34% and 36%, respectively), for white blood cells (WBCs) 3 and 6 hours after diving (20% and 25%, respectively), for lymphocytes (20%) and monocytes (23%) 6 hours after diving. A statistically significant decrease and difference judging against DSB was found: immediately after diving for monocytes (- 15%), 3 and 6 hours after diving for red blood cells (RBCs) (- 2.6% and -2.9%, respectively), haemoglobin (- 2.1% and - 2.8%, respectively) and haematocrit (- 2.4% and - 3.2%, respectively). A clinically significant change was not found for any of the test parameters when compared to RCV.

Conclusions

Observed statistically significant changes after recreational scuba diving; WBCs, neutrophils, lymphocytes, monocytes increase and RBCs, haemoglobin, haematocrit decrease, probably will not affect clinical decision.

Preanalytical external quality assessment of the Croatian Society of Medical Biochemistry and Laboratory Medicine and CROQALM: finding undetected weak spots

INTRODUCTION

The aim of this paper is to present results of first two years of preanalytical external quality assessment (EQA) in Croatia.

MATERIALS AND METHODS

This paper summarizes results from 6 rounds of preanalytical EQA during 2014-2016 in 161-175 Croatian laboratories (number ranged between cycles). EQA was designed as an online survey of the compliance with National recommendations for phlebotomy (NRP). Forty-seven questions in 5 categories are analyzed (materials and equipment, patient identification, patient preparation, sampling and storage). Additionally, preanalytical cases are presented. Overall performance scores (Question score (Qscore) for compliance with NRP and Case score (Cscore) for preanalytical cases) are calculated for each question/case as a proportion of laboratories with satisfactory procedure (x 100). Qscores and Cscores ≥ 70 were classified as acceptable (maximal score = 100).

RESULTS

In investigation of compliance with NRP, acceptable Qscores were obtained for 34/47 questions. The lowest scores were observed for the availability of sterile disposable tourniquets (Qscore = 15) and safe-sharp needles (Qscore = 34), obtaining patients address as an identifier (Qscore = 21), using glycolysis inhibitor tubes for glucose concentration measurement (Qscore = 21) and verification of manufacturers declarations on temperature and time of storage (Qscore = 31). There was no statistically significant difference in overall Qscore according to different categories of phlebotomy procedures (P = 0.284). The results of preanalytical cases showed acceptable Cscore values for all cases (89-96).

CONCLUSION

First two years of preanalytical EQA showed good compliance with the NRP and excellent expertise in resolving complex preanalytical issues. Major critical spots are lack of availability of safe-sharp needles, disposable tourniquets and glucose inhibitor tubes.

Patient safety is not compromised by excluding microscopic examination of negative urine dipstick

Background Microscopic examination of samples with negative dipstick results is not necessary. The aims of this study were to: (i) assess the risk of excluding urine sediment examination with negative dipstick results and (ii) calculate time savings by introducing this process. Methods The risk analysis was done for samples with negative urine dipstick and positive sediment findings. Possible missed elements in sediment were defined as 21 errors. Time saving was calculated as average time for preparation and examination sediments. Data were presented as counts and percentages. Results Out of 2997 samples, negative dipstick results were reported for 926 (30.6%) samples, out of which, microscopic examinations were positive for 527 (17.6%) samples. 18/21 errors were detected, with missing <5 squamous epithelial cells (SQEC) and bacteria 1+ as the most frequent ones (22.7% and 22.4%, respectively). Errors with the intermediate risk for patients were missing to report: ≥5 SQEC, ≥5 transitional epithelial cells, ≥10 hyaline casts (11.9%, 0.21%, 0.32%, respectively). Errors associated with high risk were not detected. Estimated total time saving is more than 25 h/month. Conclusions Microscopic examination of urine samples with negative dipstick results can be excluded without risk for patients and can result with considerable time savings.

Is peritoneal dialysis causing a measurable burden of inflammatory and endothelial injury on top of metabolic syndrome?

PURPOSE

Low-grade chronic inflammation is present in patients on peritoneal dialysis (PD) and in metabolic syndrome (MS). Due to possible greater endothelial changes in dialyzed patients, inflammatory response and oxidative stress are probably stronger in patients on PD. The objective of the study was to investigate possible in between adipokines, inflammatory, endothelial and oxidative stress markers between MS patients and patients on PD.

METHODS

Concentrations of adipokines (leptin, resistin), inflammatory markers [interleukin-6 (IL-6), soluble tumor necrosis factor alpha receptor (sTNF-R), myeloperoxidase (MPO), monocyte chemoattractant protein 1 (MCP-1)] and endothelial markers [soluble intracellular adhesion molecule-1 (sICAM-1), soluble CD40 ligand (sCD40L)] were determined in 55 MS patients and 18 patients on PD, with flow cytometry, and visfatin concentration was measured with ELISA. Routine biochemistry parameters were measured on Beckman Coulter AU2700 analyzer.

RESULTS

Patients on PD have significantly higher concentration of: CRP [6.5 (3.7-12.1) versus 2.6 (1.3-4.0) mg/L, P < 0.001], IL-6 [13.83 (8.48-31.31) versus 2.05 (0.67-4.11) pg/mL, P < 0.001], MCP-1 [2172.28 (1563.84-2922.77) versus 1353.58 (1166.33-1961.70) pg/mL, P = 0.023], sTNF-R [18.25 (12.81-25.22) versus 1.23 (0.89-1.43) ng/mL, P < 0.001] and sICAM-1 [830.03 (599.21-967.02) versus 463.85 (315.25-751.71) ng/mL, P = 0.006] than subjects with MS. MS patients have higher concentrations of MPO [175.47 (120.15-231.67) versus 101.76 (53.55-186.06) ng/mL, P = 0.016] and visfatin [1.5 (0.9-2.3) versus 0.9 (0.6-1.6) ng/mL, P = 0.013].

CONCLUSION

In patients on PD, inflammatory reaction is higher than in patients with MS. On the contrary, patients with MS have stronger oxidative stress response and adipose tissue activity caused probably by the chronic low level of inflammation and underlying metabolic disorders.

Compliance of blood sampling procedures with the CLSI H3-A6 guidelines: An observational study by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) working group for the preanalytical phase (WG-PRE)

BACKGROUND

An observational study was conducted in 12 European countries by the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for the Preanalytical Phase (EFLM WG-PRE) to assess the level of compliance with the CLSI H3-A6 guidelines.

METHODS

A structured checklist including 29 items was created to assess the compliance of European phlebotomy procedures with the CLSI H3-A6 guideline. A risk occurrence chart of individual phlebotomy steps was created from the observed error frequency and severity of harm of each guideline key issue. The severity of errors occurring during phlebotomy was graded using the risk occurrence chart.

RESULTS

Twelve European countries participated with a median of 33 (18-36) audits per country, and a total of 336 audits. The median error rate for the total phlebotomy procedure was 26.9 % (10.6-43.8), indicating a low overall compliance with the recommended CLSI guideline. Patient identification and test tube labelling were identified as the key guideline issues with the highest combination of probability and potential risk of harm. Administrative staff did not adhere to patient identification procedures during phlebotomy, whereas physicians did not adhere to test tube labelling policy.

CONCLUSIONS

The level of compliance of phlebotomy procedures with the CLSI H3-A6 guidelines in 12 European countries was found to be unacceptably low. The most critical steps in need of immediate attention in the investigated countries are patient identification and tube labelling.

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples

Endogenous interferences are an important source of biased laboratory results. Hemolysis, lipemia and icteria are the main source of endogenous interference in laboratory medicine. Accreditation according to ISO 15189 improves the overall quality of the laboratory procedures. The aim of our study was i) to assess the level of knowledge of Croatian medical biochemists about the proper detection and management of hemolysis, lipemia and icteria; and ii) to identify possible differences in the level of knowledge respective to the laboratory accreditation status.

An on-line self-report survey was carried out by the Working Group for Preanalytical Phase of the Croatian Society of Medical Biochemistry and Laboratory Medicine during April to May 2015. Survey included 14 statements (Q1–Q14) about procedures for samples with interferences and participants were asked to assess the degree of agreement with the statement using a 4-point Likert scale.

The lowest level of knowledge was observed for statements Q10 (dealing with icteric sample; 40.9% participants agreed with the correct procedure), Q12 (allowable error for interference; 47.2%) and Q11 (dealing with lipemic sample; 60.1%). Almost all participants (97.4%) agreed that laboratories in Croatia should have a harmonized protocol for management of samples with interferences. Participants from accredited laboratories showed higher knowledge of hemolysis detection (p=0.031), rejection of hemolyzed sample (p<0.001), management of icteric samples (p=0.038) and allowable error for interferences (p=0.040).

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples. Accreditation is associated with higher knowledge about management of samples with interferences.

The quality and scope of information provided by medical laboratories to patients before laboratory testing: Survey of the Working Group for Patient Preparation of the Croatian Society of Medical Biochemistry and Laboratory Medicine

INTRODUCTION

The aim of this work was to evaluate to what extent the scope and content of information provided to patients is standardized across medical biochemistry laboratories in Croatia.

MATERIALS AND METHODS

Two on-line self-report surveys were sent out: Survey A regarding attitudes on importance of patient preparation and Survey B on the contents of patient preparation instructions.

RESULTS

13/118 laboratories (11%) do not provide written instructions to patients on how to prepare for laboratory testing, and 36 (40%) do not include information about water intake in their instructions. Only half of laboratories provide instructions for prostate-specific antigen (53.8%), female sex hormones (53.7%) and therapeutic drug monitoring (TDM) (52.5%). Inadequate information about fasting status (55.0%) and 24 hour urine collection (77.9%) were frequent errors with high severity and were associated with the greatest potential to cause patient harm.

CONCLUSIONS

Laboratory professionals in Croatia have a positive attitude towards the importance of patient preparation for laboratory testing. However, the information for laboratory testing is not standardized and frequently lacks guidance for tests related to TDM, coagulation and endocrinology. This study highlights the need for standardized, updated and evidence-based recommendations for patient preparation in order to minimize the risk for patients.

Croatian survey on critical results reporting

INTRODUCTION

Poor harmonization of critical results management is present in various laboratories and countries, including Croatia. We aimed to investigate procedures used in critical results reporting in Croatian medical biochemistry laboratories (MBLs).

MATERIALS AND METHODS

An anonymous questionnaire, consisting of 24 questions/statements, related to critical results reporting procedures, was send to managers of MBLs in Croatia. Participants were asked to declare the frequency of performing procedures and degree of agreement with statements about critical values reporting using a Likert scale. Total score and mean scores for corresponding separate statements divided according to health care setting were calculated and compared.

RESULTS

Responses from 111 Croatian laboratories (48%) were analyzed. General practice laboratories (GPLs) more often re-analyzed the sample before reporting the critical result in comparison with the hospital laboratories (HLs) (score: 4.86 (4.75-4.96) vs. 4.49 (4.25-4.72); P=0.001) and more often reported the critical value exclusively to the responsible physician compared to HLs (4.46 (4.29-4.64) vs. 3.76 (3.48-4.03), P<0.001). High total score (4.69 (4.56-4.82)) was observed for selection of the critical results list issued by the Croatian Chamber of Medical Biochemistry (CCMB) indicating a high harmonization level for this aspect of critical result management. Low total scores were observed for the statements regarding data recording and documentation of critical result notification.

CONCLUSIONS

Differences in practices about critical results reporting between HLs and GPLs were found. The homogeneity of least favorable responses detected for data recording and documentation of critical results notification reflects the lack of specific national recommendations.

How to assess the quality of your analytical method?

Laboratory medicine is amongst the fastest growing fields in medicine, crucial in diagnosis, support of prevention and in the monitoring of disease for individual patients and for the evaluation of treatment for populations of patients. Therefore, high quality and safety in laboratory testing has a prominent role in high-quality healthcare. Applied knowledge and competencies of professionals in laboratory medicine increases the clinical value of laboratory results by decreasing laboratory errors, increasing appropriate utilization of tests, and increasing cost effectiveness. This collective paper provides insights into how to validate the laboratory assays and assess the quality of methods. It is a synopsis of the lectures at the 15th European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Continuing Postgraduate Course in Clinical Chemistry and Laboratory Medicine entitled “How to assess the quality of your method?” (Zagreb, Croatia, 24–25 October 2015). The leading topics to be discussed include who, what and when to do in validation/verification of methods, verification of imprecision and bias, verification of reference intervals, verification of qualitative test procedures, verification of blood collection systems, comparability of results among methods and analytical systems, limit of detection, limit of quantification and limit of decision, how to assess the measurement uncertainty, the optimal use of Internal Quality Control and External Quality Assessment data, Six Sigma metrics, performance specifications, as well as biological variation. This article, which continues the annual tradition of collective papers from the EFLM continuing postgraduate courses in clinical chemistry and laboratory medicine, aims to provide further contributions by discussing the quality of laboratory methods and measurements and, at the same time, to offer continuing professional development to the attendees.

Preanalytical quality improvement: in quality we trust

Total quality in laboratory medicine should be defined as the guarantee that each activity throughout the total testing process is correctly performed, providing valuable medical decision-making and effective patient care. In the past decades, a 10-fold reduction in the analytical error rate has been achieved thanks to improvements in both reliability and standardization of analytical techniques, reagents, and instrumentation. Notable advances in information technology, quality control and quality assurance methods have also assured a valuable contribution for reducing diagnostic errors. Nevertheless, several lines of evidence still suggest that most errors in laboratory diagnostics fall outside the analytical phase, and the pre- and postanalytical steps have been found to be much more vulnerable. This collective paper, which is the logical continuum of the former already published in this journal 2 years ago, provides additional contribution to risk management in the preanalytical phase and is a synopsis of the lectures of the 2nd European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)-Becton Dickinson (BD) European Conference on Preanalytical Phase meeting entitled "Preanalytical quality improvement: in quality we trust" (Zagreb, Croatia, 1-2 March 2013). The leading topics that will be discussed include quality indicators for preanalytical phase, phlebotomy practices for collection of blood gas analysis and pediatric samples, lipemia and blood collection tube interferences, preanalytical requirements of urinalysis, molecular biology hemostasis and platelet testing, as well as indications on best practices for safe blood collection. Auditing of the preanalytical phase by ISO assessors and external quality assessment for preanalytical phase are also discussed.

Lipemia: causes, interference mechanisms, detection and management

In the clinical laboratory setting, interferences can be a significant source of laboratory errors with potential to cause serious harm for the patient. After hemolysis, lipemia is the most frequent endogenous interference that can influence results of various laboratory methods by several mechanisms. The most common preanalytical cause of lipemic samples is inadequate time of blood sampling after the meal or parenteral administration of synthetic lipid emulsions. Although the best way of detecting the degree of lipemia is measuring lipemic index on analytical platforms, laboratory experts should be aware of its problems, like false positive results and lack of standardization between manufacturers. Unlike for other interferences, lipemia can be removed and measurement can be done in a clear sample. However, a protocol for removing lipids from the sample has to be chosen carefully, since it is dependent on the analytes that have to be determined. Investigation of lipemia interference is an obligation of manufacturers of laboratory reagents; however, several literature findings report lack of verification of the declared data. Moreover, the acceptance criteria currently used by the most manufacturers are not based on biological variation and need to be revised. Written procedures for detection of lipemia, removing lipemia interference and reporting results from lipemic samples should be available to laboratory staff in order to standardize the procedure, reduce errors and increase patient safety.

The evaluation and comparison of consecutive high speed centrifugation and LipoClear® reagent for lipemia removal

BACKGROUND

The aim of this study was to evaluate and compare the efficiency of high speed centrifugation and LipoClear® reagent for lipemia removal in plasma samples spiked with Intralipid®, for 26 biochemistry analytes.

MATERIALS AND METHODS

A plasma pool was collected. Aliquots of the pool were spiked with Intralipid® (final concentrations of 300mg/dL and 500mg/dL Intralipid®). The lipemia was removed from the aliquots by high speed centrifugation or LipoClear® reagent. 26 analytes were determined in native, lipemic plasma and in samples after lipemia removal. The bias from the concentration in the native sample was calculated for each parameter for Intralipid® concentrations, 300 and 500mg/dL of Intralipid®, respectively. Also, the recovery for each parameter after processing the samples using high speed centrifugation and LipoClear® was calculated. The biases and test recoveries were compared with the desirable specification for imprecision (DSI) according to Ricos available at the Wesgard's website. The bias and recovery for procalcitonin were compared with DSI according to Barassi and colleagues.

RESULTS

The bias of the spiked samples exceeded the DSI at 300mg/L Intralipid® for creatinine, glucose, total protein, iron and albumin; and for all previously mentioned parameters including CK-MB, sodium, potassium, chlorides, magnesium and ALP at concentration of 500mg/L Intralipid®. For the test recovery the DSI criteria were not met for calcium, total protein, sodium and chlorides after high speed centrifugation and for glucose, calcium, phosphates, magnesium, sodium, potassium, chlorides, ALP, GGT, CK-MB, total protein, albumin and troponin T after using LipoClear®.

CONCLUSIONS

LipoClear® is not suitable for lipemia removal from samples designated for glucose, sodium, potassium, chlorides, phosphates, magnesium, CK-MB, ALP, GGT, total protein, albumin, CRP and troponin T measurements. High speed centrifugation should be used for lipemia removal instead for glucose, potassium, phosphates, magnesium, CK-MB, ALP, GGT, albumin, CRP and TnT measurements.

Croatian Society of Medical Biochemistry and Laboratory Medicine: national recommendations for venous blood sampling

Phlebotomy is one of the most complex medical procedures in the diagnosis, management and treatment of patients in healthcare. Since laboratory test results are the basis for a large proportion (60-80%) of medical decisions, any error in the phlebotomy process could have serious consequences. In order to minimize the possibility of errors, phlebotomy procedures should be standardised, well-documented and written instructions should be available at every workstation. Croatia is one of the few European countries that have national guidelines for phlebotomy, besides the universally used CLSI (Clinical Laboratory Standards Institute) H3-A6 Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture; approved Standard-Sixth Edition (CLSI, 2007) and WHO (World Health Organization) guidelines on drawing blood: best practices in phlebotomy (WHO, 2010). However, the growing body of evidence in importance of preanalytical phase management resulted in a need for evidence based revision and expansion of existing recommendations. The Croatian Society for Medical Biochemistry and Laboratory Medicine, Working Group for the Preanalytical Phase issued this recommendation. This document is based on the CLSI guideline H3-A6, with significant differences and additional information.

Heterogeneity of manufacturers' declarations for lipemia interference--an urgent call for standardization

INTRODUCTION

Due to the budget limitations, laboratories mostly rely on the manufacturers' information about the influence of interfering substances on laboratory results. However, some manufacturers do not follow the recommended procedures for testing interferences (CLSI standard) and there is a great variability in the presentation of data regarding lipemia interference.

MATERIALS AND METHODS

We aimed to verify the manufacturers' specifications for lipemia interference for clinical chemistry reagents provided by Beckman Coulter, Roche and Siemens. Bias was determined using the Intralipid® simulated lipemic samples. Furthermore, we aimed to compare obtained data with the manufacturers' claims and desirable specification for imprecision derived from biological variation.

RESULTS

i) Manufacturers' declarations were not confirmed for all three manufacturers; ii) the magnitude and direction of the effect of lipemia on laboratory results differ substantially between the three tested analytical systems; and iii) manufacturers are using arbitrary limits in declaring the expected effect of interference on laboratory results.

CONCLUSIONS

There is an urgent need to standardize the way manufacturers test and report their data on the lipemia interference. We propose that, instead of arbitrary limits, manufacturers use evidence based quality specifications for assessing the allowable biases. Moreover, laboratories should be aware of the possible lack of replicability of manufacturers' declarations.

Association of APOA5 -1131T>C polymorphism and serum lipid levels in patients with type 2 diabetes

Significant abnormalities in lipid metabolism are frequently present in patients with type 2 diabetes mellitus (T2DM). Hypertriglyceridemia, a highly proatherogenic state, is associated with increased risk of coronary artery disease. Genetic polymorphism APOA5 -1131T>C has been recognized as a significant contributor to hypertriglyceridemia in both healthy and diabetic populations. The aim of the study was to investigate the association of APOA5 -1131T>C polymorphism with the serum levels of triglycerides, total cholesterol, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol in patients with T2DM. In total, 234 DNA samples from patients with T2DM were genotyped using the PCR-RFLP method. Serum lipid levels were measured using standard laboratory methods. Obtained APOA5 -1131T>C genotype frequencies were 89% (T/T) and 11% (T/C+C/C). There was no significant association between APOA5 -1131T>C genotypes and triglyceride levels (1.90 mM [1.32-2.74] vs. 1.78 mM [1.54-3.05] for T/T vs. T/C+C/C genotype; p=0.553), HDL cholesterol levels (1.30 mM [1.10-1.40] vs. 1.30 mM [1.05-1.40] for T/T vs. T/C+C/C; p=0.534), and LDL cholesterol levels (3.1 mM [2.3-3.8] vs. 3.0 mM [2.2-3.5] for T/T vs. T/C+C/C; p=0.313). Our results suggest that hypertriglyceridemia in patients with T2DM is not likely to be associated with the APOA5 -1131T>C polymorphism.

The effect of high-calorie meal consumption on oxidative stress and endothelial dysfunction in healthy male adults

Several authors have reported the association of postprandial hypertriglyceridemia with oxidative stress, systemic inflammation and endothelial dysfunction. Our aim was to investigate the effect of high-calorie meal on blood markers of oxidative stress and endothelial dysfunction and the association of APOA5 -1131T/C and -250G/A hepatic lipase (HL) polymorphisms with postprandial triglyceride response. This study included 102 healthy male volunteers. All participants consumed a high-calorie meal (823 calories, 50 g fat, 28 g protein, 60 g carbohydrates). Total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, hsCRP, TAS and ICAM-1 were measured at fasting state and postprandially. APOA5 -1131T/C and -250G/A HL polymorphisms were also determined. Postprandial triglycerides were significantly increased (1.4 (1.1-2.1) vs. 2.4 (1.9-3.3) mmol/l, P<0.001). Average triglyceride increase was 1.0+/-0.7 mmol/l (65 %). Concentration of triglycerides, HDL-cholesterol, LDL-cholesterol, TAS and ICAM-1 differed significantly between the fasting state and postprandial measurements (P<0.001). However, those differences were within the limits of analytical imprecision. Other parameters did not change 3 h after the meal. Triglycerides response did not differ respective to the APOA5 and HL polymorphisms. Family history of hypertension and acute myocardial infarction were associated with higher postprandial triglyceride concentrations. Postprandial hypertriglyceridemia is not associated with increased concentrations of hsCRP, TAS and ICAM-1. Furthermore, APOA5 -1131T/C and -250G/A HL polymorphisms are not associated with different postprandial triglyceride response.

Symptomatic cardiac metastases of breast cancer 27 years after mastectomy: a case report with literature review--pathophysiology of molecular mechanisms and metastatic pathways, clinical aspects, diagnostic procedures and treatment modalities

Metastases to the heart and pericardium are rare but more common than primary cardiac tumours and are generally associated with a rather poor prognosis. Most cases are clinically silent and are undiagnosed in vivo until the autopsy. We present a female patient with a 27-year-old history of an operated primary breast cancer who was presented with dyspnoea, paroxysmal nocturnal dyspnoea and orthopnoea. The clinical signs and symptoms aroused suspicion of congestive heart failure. However, the cardiac metastases were detected during a routine cardiologic evaluation and confirmed with computed tomography imaging. Additionally, this paper outlines the pathophysiology of molecular and clinical mechanisms involved in the metastatic spreading, clinical presentation, diagnostic procedures and treatment of heart metastases. The present case demonstrates that a complete surgical resection and systemic chemotherapy may result in a favourable outcome for many years. However, a lifelong medical follow-up, with the purpose of a detection of metastases, is highly recommended. We strongly call the attention of clinicians to the fact that during the follow-up of all cancer patients, such heart failure may be a harbinger of the secondary heart involvement.

Visfatin is not associated with inflammatory markers in patients on hemodialysis

BACKGROUND

Cardiovascular events are a major cause of death in patients with end-stage renal disease. Endothelial dysfunction represents a key event in atherosclerosis development and has been implicated in the pathophysiology of different forms of cardiovascular disease, including chronic kidney disease. In recent years, visfatin, a ubiquitous adipokine, has been described as a potent marker of endothelial inflammation and dysfunction. The aim of the study was to investigate the association of visfatin with well-known markers of inflammation and endothelial dysfunction.

METHODS

Serum and plasma samples from 66 patients (40 males and 26 females) treated by hemodialysis were analysed for visfatin, fibrinogen, CRP, PAI-1 levels. Visfatin was determined by ELISA method while CRP, fibrinogen and PAL-1 were obtained by standard laboratory methods.

RESULTS

We observed statistically significant correlation between visfatin level and fibrinogen (r = 0.51; p = 0.008) and the time on dialysis in female patients (r = 0.70; p < 0.001). PAI-1 and CRP did not correlate with visfatin in males nor in females.

CONCLUSIONS

Visfatin is correlated with time on dialysis and with fibrinogen only in female dialysis patients. To confirm this, further studies are needed with a higher number of patients.

ABCC8 polymorphisms are associated with triglyceride concentration in type 2 diabetics on sulfonylurea therapy

BACKGROUND

The failure of therapy with oral hypoglycemic drugs leads to not only poorly regulated glycemic status, but also dyslipidemia and increased body weight and body mass index (BMI). Sulfonylureas act as insulin secretagogues by binding to the sulfonylurea receptor (SUR-1) encoded by the gene ABCC8. The aim of this study was to explore whether there is an association of ABCC8 polymorphisms SUR1 exon 16 (-3C/T), SUR-1 exon 31 (Arg1273Arg), and SUR-1 exon 33 (S1369A) with lipid concentration and BMI in type 2 diabetics on sulfonylurea therapy.

MATERIALS AND METHODS

This study included 251 unrelated type 2 diabetics on sulfonylurea therapy. Height and weight were measured for BMI calculation. All polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism methods. Lipid concentrations and BMI were measured at inclusion into the study and after 6 months of follow-up.

RESULTS

Wild-type allele carriers for the SUR-1 exon 31 polymorphism (Arg1273Arg) had a significantly higher triglyceride (TG) concentration when compared with the carriers of two variant alleles (p=0.023). Polymorphic allele carriers of the SUR-1 exon 16 (-3C/T) polymorphism were more frequent in the subgroup of patients with the TG concentration increase after 6 months (p for genotype and allelic differences: 0.024 and 0.015, respectively).

CONCLUSION

ABCC8 polymorphisms in exon 16 and 31 are associated with the TG concentration in type 2 diabetics on sulfonylurea therapy.

The association of uric acid with glucose and lipids in general population: Croatian cross-sectional study

Hyperuricemia may have an important role in metabolic syndrome, cardiovascular diseases and stroke. Elevated serum uric acid concentration has been shown to be the strong predictor of cardiovascular mortality in several recently published studies. Our aim was to determine the prevalence of hyperuricemia in general Croatian population and to investigate the association of serum uric acid with glucose and lipids. This was a retrospective cross-sectional study on 6,476 consecutive adults. Prevalence of hyperuricemia was 13.9% in general population and it was significantly higher in males, than in females (26% vs. 6%; p < 0.001). Median uric acid concentration was higher in males than in females (343 vs. 238 micromol/L; p < 0.001). Age, glucose and lipid parameters did not correlate with uric acid. In hyperuricemic subjects, increased concentrations of glucose (33.1% vs. 13.1%; p < 0.001), triglycerides (46.9% vs. 17.6%; p < 0.001), total cholesterol (69.6% vs. 51.9%; p < 0.001), LDL-cholesterol (64.5% vs. 46.4%; p < 0.001) and decreased concentration of HDL-cholesterol (24.3% vs. 13.0%; p < 0.001) were more prevalent than in subjects with normal serum concentrations of uric acid. Hyperuricemia is highly prevalent in Croatian general population and it aggregates with hyperglycemia and dyslipidemia.

Insulin receptor H1085H C>T and insulin receptor substrate 1 G972R polymorphisms and prostate cancer risk: a pilot study

BACKGROUND

In recent years, numerous studies have focused their attention on genes that are part of the insulin/insulin-like growth factor 1 signaling pathway, such as the insulin receptor (INSR) and the insulin receptor substrate 1 (IRS1) genes.

AIM

We aimed to examine the association of INSR H1085H C>T and IRS1 G972R polymorphisms with prostate cancer (PC). We also aimed to examine possible association with cancer severity assessed by Gleason score.

MATERIALS AND METHODS

We have studied 180 consecutive patients referred for PC screening. The genotyping of two polymorphisms (INSR H1085H C>T and IRS1 G972R) was performed by the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

There was no difference in genotype (p=0.794) or allelic (p=0.621) frequency of the IRS1 G972R polymorphism between PC (n=119) and control (n=61) groups. However, a significant difference was found in INSR H1085H C>T polymorphism genotype and allelic distribution. Carriers of the polymorphic allele (C/T+T/T) were more frequent in control group patients than in the PC group (54.10% vs. 37.82%; p=0.040; odds ratio [95% confidence interval]=0.52 [0.28-0.96]). The IRS1 and INSR polymorphism distribution did not differ in subgroups according to Gleason score.

CONCLUSION

INSR H1085H C>T polymorphism seems to be associated with PC risk, whereas IRS1 G972R is not. However, because of the limited power of this study, there is a possibility that some modest effects of the IRS1 G972R polymorphism on PC risk went undetected. Neither polymorphism is associated with the degree of PC malignancy.

The prevalence of preanalytical errors in a Croatian ISO 15189 accredited laboratory

BACKGROUND

The preanalytical phase is the most common source of laboratory errors. The goal of this descriptive study was to analyze the prevalence and type of preanalytical errors in relation to the site of sample collection (inpatient vs. outpatient) and the type of laboratory unit (hematology and coagulation vs. biochemistry). For the biochemistry unit, the data were also analyzed relative to the type of the analysis (stat vs. routine).

METHODS

We retrospectively analyzed the sample and test request form error rate for a 1-year period, from January to December 2008.

RESULTS

The frequency of the sample errors differed significantly between the emergency and routine biochemistry unit (0.69% vs. 2.14%; p<0.0001), and between inpatients and outpatients (1.12% vs. 1.36%; p=0.0006). Hemolysis was the most frequent sample error, accounting for 65% of all unsuitable specimens in the emergency biochemistry unit. The total sample error rate did not differ between hematology and coagulation vs. the biochemistry unit. The frequency of test request form errors differed significantly with respect to the sample collection site (p<0.0001), laboratory unit (p<0.0001) and type of the analysis (p<0.0001). Errors in the test request form were least frequent in the outpatient unit (2.98%) and most frequent in the routine biochemistry unit (65.94%).

CONCLUSIONS

Sample and test request form errors in our laboratory are occurring with a frequency comparable to that reported by others. Continuous educational action is needed for all stakeholders involved in laboratory testing to improve the quality of the preanalytical phase of the total testing process.

Comparison of visual vs. automated detection of lipemic, icteric and hemolyzed specimens: can we rely on a human eye?

BACKGROUND

Results from hemolyzed, icteric, and lipemic samples may be inaccurate and can lead to medical errors. These preanalytical interferences may be detected using visual or automated assessment. Visual inspection is time consuming, highly subjective and not standardized. Our aim was to assess the comparability of automated spectrophotometric detection and visual inspection of lipemic, icteric and hemolyzed samples.

METHODS

This study was performed on 1727 routine biochemistry serum samples. Automated detection was performed using the Olympus AU2700 analyzer. We assessed: 1) comparability of visual and automated detection of lipemic, icteric and hemolyzed samples, 2) precision of automated detection, and 3) inter-observer variability for visual inspection.

RESULTS

Weighted kappa coefficients for comparability of visual and automated detection were: 0.555, 0.529 and 0.638, for lipemic, icteric and hemolyzed samples, respectively. The precision for automated detection was high for all interferences, with the exception of samples being only slightly lipemic. The best overall agreement between observers was present in assessing lipemia (mean weighted kappa=0.698), whereas the lowest degree of agreement was observed in assessing icterus (mean weighted kappa=0.476).

CONCLUSIONS

Visual inspection of lipemic, icteric and hemolyzed samples is highly unreliable and should be replaced by automated systems that report serum indices.

Efficiency of test report delivery to the requesting physician in an outpatient setting: an observational study

BACKGROUND

Clinical laboratories accredited according to ISO 15189 quality standards are obliged to implement and continuously monitor quality indicators for evaluation of the laboratory's contribution to patient care. Reporting laboratory results to the requesting physician is one important phase of the clinical laboratory testing process. Failure to report results may indicate the ineffectiveness of the laboratory service. We aimed to analyze the proportion and type of laboratory reports for outpatients that were not delivered to the requesting physician.

METHODS

This retrospective observational study was conducted during an 11-month period from January to December 2007 at our outpatient biochemistry laboratory unit. Data on demographic characteristics, request types and laboratory findings for all uncollected reports were retrieved from the laboratory information system and compared with one random 2-week representative period.

RESULTS

During the study period our laboratory issued 22,445 patient reports with more than 150,000 biochemistry analyses. Of these, 464 (2.1%) were uncollected laboratory reports. When compared to the representative period, patients who never collected their laboratory reports were younger (p<0.001) or suffering from some chronic disease. Routine biochemistry tests were the most prevalent (>50%). The majority of routine biochemistry tests were almost equally represented during the study and representative period, while molecular diagnostic tests were several times more frequently uncollected (p<0.001). Reports with electrolytes, metabolites and glucose were the least likely to be uncollected (p<0.001). The total cost for those tests was 30% of the average monthly laboratory budget.

CONCLUSIONS

A significant amount of the laboratory budget is wasted for tests that never reach the requesting physician. Such misutilization of the laboratory reveals the substantial lack of medical necessity for test requests. Further studies are needed to explore the possible efficiency of the various interventions in reducing the volume of unnecessary and erroneous testing.

Pro-inflammatory and anti-inflammatory cytokines in acute ischemic stroke and their relation to early neurological deficit and stroke outcome

OBJECTIVES

Our aim was to explore (i) the difference in concentration of IL-6, TNF-alpha and IL-10 between acute ischemic stroke patients and control individuals; (ii) the association of plasma cytokine concentration with stroke severity at admission assessed by NIHSS and stroke outcome in 90 days assessed by Barthel index (BI) and modified Rankin scale (mRS).

MATERIALS AND METHODS

Study included 68 stroke patients admitted within 12 h of symptoms onset and 71 controls.

RESULTS

IL-6 was increased in patients relative to controls (P=0.035) and this increase was associated with severe stroke (P=0.007) and worse outcome (P=0.030 and 0.019; assessed by BI and mRS, respectively), whereas IL-10 was decreased (P=0.044) and associated with better outcome (P=0.043). TNF-alpha did not differ between studied groups (P=0.302).

CONCLUSIONS

Increased IL-6 and reduced IL-10 concentrations are present in early stroke period and are associated with a degree of neurological deficit and/or stroke outcome.

Rare TA repeats in promoter TATA box of the UDP glucuronosyltranferase (UGT1A1) gene in Croatian subjects

BACKGROUND

Gilbert's syndrome is a chronic or recurrent mild unconjugated hyperbilirubinemia caused by decreased activity of UDP glucuronosyltranferase (UGT1A1). The most common cause of Gilbert's syndrome in Caucasians is homozygous variant of the A(TA)7TAA promoter polymorphism. Alleles with five or eight TA repeats have also been described, but they are very rare in Caucasian populations.

METHODS

Over a 6-year period (2001-2006), 1109 subjects with suspected Gilbert's syndrome were included in this study. Genotyping of (TA)6 and (TA)7 alleles was performed using high-resolution electrophoretic separation of amplified PCR products on Spreadex EL300 gels. In seven subjects, aberrant electrophoretic patterns were observed and additionally sequenced on an ABI Prism 310 Genetic Analyzer.

RESULTS

Genotype distributions for 1102 subjects with (TA)6 or (TA)7 alleles were as follows: 54.10%, 26.33% and 18.94% for the (TA)7/(TA)7, (TA)6/(TA)7 and (TA)6/(TA)6, respectively. Sequencing of seven samples that could not be identified as one of these alleles identified four subjects with the (TA)5/(TA)7, two with the (TA)7/(TA)8 and one with the (TA)6/(TA)8 genotype.

CONCLUSION

Genotyping of TA repeats in the promoter region of the UGT1A1 gene revealed the presence of rare alleles with five or eight TA repeats, with a very high frequency of the (TA)7 allele in subjects suspected of having Gilbert's syndrome.

Methodological Issues in Genetic Association Studies of Inherited Thrombophilia: Original Report of Recent Practice

The aims of this article are to evaluate the methodological quality of genetic association studies on the inherited thrombophilia published during 2003 to 2005, to identify the most common mistakes made by authors of those studies, and to examine if overall quality of the article correlates with the quality of the journal. Articles were evaluated by 2 independent reviewers using the checklist of 16 items. A total of 58 eligible studies were identified. Average total score was 7.59 ± 1.96. Total article score did not correlate with the journal impact factor (r = 0.3971; 95% confidence interval [CI], 0.1547-0.5944, P = .002). Total score did not differ across years ( P = .624). Finally, it is concluded that methodological quality of genetic association studies is not optimal, and it does not depend on the quality of the journal. Journals should adopt methodological criteria for reporting the genetic association studies, and editors should encourage authors to strictly adhere to those criteria.

The methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and cancer risk: The Croatian case–control study

OBJECTIVES

Methylation abnormalities appear to be important for the pathogenesis of many cancer types. Since methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the methylation process catalyzing reduction of 5,10-methylenetetrahydrofolate to 5-methyl-tetrahydrofolate, C677T polymorphism, which decreases enzyme activity, may be associated with cancer susceptibility. The aim of this work was to investigate the distribution of MTHFR C677T polymorphism between various types of cancer and cancer-free controls and to assess if there is a difference in frequency.

MATERIALS AND METHODS

269 Cancer cases (95 prostate cancer, PC; 81 head and neck, HN; and 93 breast cancers, BC) and 102 healthy controls, free of cancer, were genotyped for C677T MTHFR polymorphism using the PCR-RFLP method.

RESULTS

There was no overall difference in C677T genotype distribution between total cancer cohort and controls (p=0.064). However, a significant difference and protective OR was found for the C/T genotype (OR=0.574, 95% CI=0.352-0.935). In a comparison of different cancer types and respective controls, genotype frequencies were significantly different between head and neck carcinoma and controls (p=0.004), again with protective role of C/T genotype (OR=0.356, 95% CI=0.189-0.671). Moderate overrepresentation of C/T was found in respective male controls when compared with prostate cancer patients (p value was 0.074 for C/T vs. C/C comparison). The OR for heterozygous C/T genotype in prostate cancer group was 0.404, pointing to its putative protective role. Genotype and allelic frequencies did not differ significantly between 93 breast cancer patients and their 65 age-matched female controls.

CONCLUSION

Our data indicate that the C677T MTHFR polymorphism does not significantly contribute to the inherited genetic susceptibility to breast and prostate cancer, while we show some evidence for possible genetic contribution of this polymorphism to the development of head and neck carcinoma.