Laboratory medicine in arterial hypertension.

In the initial diagnostics of arterial hypertension (AH) laboratory medicine is a cornerstone, along with a blood pressure (BP) measurement and an electrocardiogram. It mainly refers to routine blood and urine tests for diagnosis and monitoring primary hypertension and its associated conditions such as asymptomatic hypertension-mediated organ damage, chronic kidney disease and hypertensive disorders of pregnancy. In addition, long term non-fatal and fatal risks for cardiovascular (CV) events in hypertension are assessed based on clinical and laboratory data. Furthermore, laboratory medicine is involved in the management of hypertension, especially in monitoring the disease progression. However, antihypertensive drugs may interfere with laboratory test results. Diuretics, especially thiazides, can affect blood and urine sodium concentrations, or angiotensin-converting enzyme inhibitors and angiotensin receptor blockers can affect the blood biomarkers of the renin-angiotensin-aldosterone system (RAAS). It's dysfunction plays a critical role in primary aldosteronism (PA), the most common endocrine disorder in secondary hypertension, which accounts for only small proportion of AH in relative terms but substantial proportion of hypertensives in absolute terms, affecting younger population and carrying a higher risk of CV mortality and morbidity. When screening for PA, aldosterone-to-renin ratio still contributes massively to the increased incidence of the disease, despite certain limits. In conclusion, laboratory medicine is involved in the screening, diagnosis, monitoring and prognosis of hypertension. It is of great importance to understand the preanalytical and analytical factors influencing final laboratory result.

Performance comparison of Westergren modified SRS 100/II and alternate iSED® method for erythrocyte sedimentation rate.

INTRODUCTION: The erythrocyte sedimentation rate (ESR) includes three phases, each prone to different interferences. Due to many disadvantages of the reference Westergren method, modified and alternate methods have been introduced. The aim of this study was to compare the modified Westergren method on SRS 100/II analyzer in citrate blood with the alternate method on iSED® analyzer in EDTA sample. Additionally, possible interfering factors and ESR stability during 6 h at room temperature were evaluated. METHODS: A total of 188 samples were included in the method comparison. Additionally, the effects of inflammation, haematocrit and MCV values on ESR were evaluated. To determine ESR stability in different samples, ESR was evaluated at three time points; within 15 min of blood sampling and after 3 and 6 h in different sample types and analyzers (N = 65). RESULTS: Results indicated the constant difference between tested methods with obtained mean bias of 5 mm (95% CI: 3-7). There was higher absolute mean bias in groups with ESR > 40 mm and elevated inflammation markers (p < 0.001). Regarding different MCV and haematocrit groups there was no statistically significant difference in obtained absolute mean biases for MCV (p = 0.087) while there was higher bias in low haematocrit group compared to normal haematocrit (p = 0.004). In addition, there was a significant difference between ESR values at different time points for iSED® (p < 0.001) and no difference for SRS 100/II analyzer (p = 0.406). CONCLUSION: There are differences in ESR values between tested methods. EDTA sample on iSED® should be analysed as soon as possible to avoid falsely increased ESR.

Interpretative comments - need for harmonization? Results of the Croatian survey by the Working Group for Post-analytics.

INTRODUCTION: Interpretation of laboratory test results is a complex post-analytical activity that requires not only understanding of the clinical significance of laboratory results but also the analytical phase of laboratory work. The aims of this study were to determine: 1) the general opinion of Croatian medical biochemistry laboratories (MBLs) about the importance of interpretative comments on laboratory test reports, and 2) to find out whether harmonization of interpretative comments is needed. MATERIALS AND METHODS: This retrospective study was designed as a survey by the Working Group for Post-analytics as part of national External Quality Assessment (EQA) program. All 195 MBLs participating in the national EQA scheme, were invited to participate in the survey. Results are reported as percentages of the total number of survey participants. RESULTS: Out of 195 MBLs, 162 participated in the survey (83%). Among them 59% MBLs implemented test result comments in routine according to national recommendations. The majority of laboratories (92%) state that interpretative comments added value to the laboratory reports, and a substantial part (72%) does not have feedback from physicians on their significance. Although physicians and patients ask for expert opinion, participants stated that the lack of interest of physicians (64%) as well as the inability to access patient's medical record (62%) affects the quality of expert opinion. CONCLUSION: Although most participants state that they use interpretative comments and provide expert opinions regarding test results, results of the present study indicate that harmonization for interpretative comments is needed.

Gastric cancer detection using the serum pepsinogen test method.

BACKGROUND: Gastric cancer (GC) is the eighth most common cause of cancer deaths in Croatia and one of the most common causes of cancer deaths worldwide. A reliable diagnostic tool for the early detection of GC is essential. OBJECTIVE: We previously suggested a pepsinogen test method to reduce the mortality from GC by allowing early detection. Here, we report an updated analysis from a prospective single-center clinical study to evaluate the sensitivity and specificity of the pepsinogen test method and to determine whether this test can be used as a part of routine laboratory assessment of high-risk patients. METHODS: We present mature data of the pepsinogen test method in the Croatian population after a median follow-up of 36 months. Statistical analyses were performed using a Mann-Whitney U test, multiple logistic regression, and receiver operating characteristics (ROC) to evaluate the predictive power of the assayed biomarkers. RESULTS: Of the 116 patients, 25 patients had GC and 91 demonstrated a nonmalignant pathology based on tissue biopsy. Cutoff values were pepsinogen I ⩽70 and pepsinogen I/II ratio ⩽3.0. Using ROC curve analysis, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were determined to be 87.22%, 78.12%, 90.10%, 71.43%, and 92.86%, respectively, for the diagnosis of GC. The area under the curve was 0.700 (95% confidence interval 0.57-0.83). CONCLUSION: Pepsinogen tests are valuable for screening a population in need of further diagnosis and could help to avoid unnecessary invasive endoscopic procedures.

The concurrence of the current postanalytical phase management with the national recommendations: a survey of the Working Group for Postanalytics of the Croatian Society of Medical Biochemistry and Laboratory Medicine.

INTRODUCTION: The detection and prevention of errors in the postanalytical phase can be done through the harmonization and standardization of constituent parts of this phase of laboratory work. The aim was to investigate how well the ongoing management of the postanalytical phase corresponds to the document "Post-analytical laboratory work: national recommendations" in Croatian medical biochemistry laboratories (MBLs). MATERIALS AND METHODS: All 195 MBLs participating in the national external quality assessment scheme, were invited to undertake a part in a survey. Through 23 questions the participants were asked about management of the reference intervals (RI), delta check, reflex/reflective testing, postanalytical quality indicators and other parts of the postanalytical phase recommended in the national recommendations. The results are presented in numbers and percentages. RESULTS: Out of 195 MBLs, 119 participated in the survey, giving a response rate of 61%. Not all of the respondents provided answers to all the questions. Delta check has not been used in 59% (70/118) of the laboratories. Only 22/113 (20%) laboratories use reflex and/or reflective testing. In 53% of the laboratories, critical results were reported within 30 minutes of the confirmation of the results. In 34% (40/118) of the laboratories, turnaround time and reporting of critical results are two most often monitored postanalytical quality indicators. CONCLUSION: The results showed the critical results reporting and monitoring of postanalytical quality indicators are in the line with the recommendations. However, the management of RI verification, the use of delta check and reflex/reflective testing still must be harmonized among Croatian MBLs.

General position of Croatian medical biochemistry laboratories on autovalidation: survey of the Working Group for Post-analytics of the Croatian Society of Medical Biochemistry and Laboratory Medicine.

INTRODUCTION: Autovalidation (AV) is an algorithm based on predefined rules designed, among others, to automate and standardize the postanalytical phase of laboratory work. The aim of this study was to examine the overall opinion of Croatian medical biochemistry laboratories regarding various aspects of AV. MATERIAL AND METHODS: This retrospective study is an analysis of the responses of a survey about AV comprised of 18 questions, as part of Module 10 ("Postanalytical phase of laboratory testing") of national External Quality Assessment program, administered by the Croatian Centre for Quality Assessment in Laboratory Medicine. Results were reported as percentages of total number of participants in survey or as proportions of observed data if the overall number of data was <100. RESULTS: 121 laboratories responded to the survey, of which 76% do not use AV, while 11% of laboratories use AV in routine laboratory work. 16/29 laboratories implemented semi-automated AV for general biochemistry (7/29), haematology (5/29), and coagulation (4/29) tests. Analytical measurement ranges, critical values, flags from analysers, interference indices and delta check were the most commonly used rules in the algorithm. 12/29 laboratories performed validation of AV with less than 500 samples (8/29). 7/13 laboratories report the percentage of AV being 20-50%, while 10/13 answered that introduction of AV significantly reduced turnaround time (TAT) (for 20 - 25%), especially for biochemistry tests. CONCLUSIONS: Despite of its numerous benefits (i.e. shorter TAT, less manual validation, standardization of the postanalytical phase), only a small number of Croatian laboratories use AV.

How well do Croatian laboratories adhere to national recommendations for laboratory diagnostics of chronic kidney disease (CKD)?

Background In 2014, the Joint Croatian Working Group (JCWG) for laboratory diagnostic of chronic kidney disease (CKD) conducted a survey across medical-biochemistry laboratories which demonstrated a large heterogeneity in this area of laboratory medicine. To ensure the tools for the standardization process, in 2017 the JCWG-CKD published the first Croatian recommendations for laboratory diagnostics of CKD. To assess the implementation process, we have repeated a survey to explore how well laboratories adhere to the recommendations. Methods An invitation to the survey was sent to all Croatian medical-biochemistry laboratories (n = 196). The questionnaire was designed in a form of 19 questions and statements, with possible multiple answers. Results The response rate was 98/196 (50.0%). The predominant method for serum creatinine measurement was the standardized compensated Jaffe method (79.2%). There was substantial decrease in the number of laboratories which measure creatinine with the non-standardized uncompensated Jaffe method, compared with the initial 2014 assessment; 7% vs. 40%, respectively. The number of the laboratories that did not report estimated glomerular filtration rate (eGFR) values decreased almost by half compared to the initial data (37.6% vs. 74.4%). However, compared to the 2014 initial assessment, a similar number of laboratories (54/98 vs. 58/80) did not measure urine albumin or protein. Conclusions The collected data showed a substantial improvement in the standardization of the serum creatinine measurement, as well as in the reporting of eGFR. However, albuminuria or proteinuria assessment is still not implemented nationwide, mainly in primary health care laboratories. This demonstrates the importance of promoting and monitoring implementation of guidelines after publication.

Post-analytical laboratory work: national recommendations from the Working Group for Post-analytics on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine.

The post-analytical phase is the final phase of the total testing process and involves evaluation of laboratory test results; release of test results in a timely manner to appropriate individuals, particularly critical results; and modification, annotation or revocation of results as necessary to support clinical decision-making. Here we present a series of recommendations for post-analytical best practices, tailored to medical biochemistry laboratories in Croatia, which are intended to ensure alignment with national and international norms and guidelines. Implementation of the national recommendations is illustrated through several examples.

Faecal calprotectin determination: impact of preanalytical sample treatment and stool consistency on within- and between-method variability.

INTRODUCTION: We assessed the differences in faecal calprotectin (FC) concentrations measured by two assays depending on the stool consistency and extraction method. MATERIALS AND METHODS: Stool samples were extracted using the EliA Stool Extraction Kit, Calex® Cap extraction device and respective weighing methods, while FC concentrations were measured using the EliATM Calprotectin and Bühlmann fCAL® Turbo method and checked for within- and between-method variability with regard to extraction method and stool consistency category. Extraction yield was evaluated for impact of different sample incubation time (10 min and 1 h) in extraction buffer for both methods and for impact of different initial sample dilutions (1:50, 1:100, 1:500) for fCAL® Turbo method. RESULTS: Results determined from Calex® Cap extracts were higher compared to weighing method extracts (mean bias 33.3%; P < 0.001), while no significant difference was found between results obtained with EliA Stool Extraction Kit and weighing method (mean bias 0.1%; P = 0.484), in both cases irrespective of stool consistency. Bühlmann fCAL® Turbo results were higher than EliATM Calprotectin results (mean bias 32.3%, P = 0.025 weighing method; and mean bias 53.9%, P < 0.001 extraction devices), the difference is dependent on stool consistency and FC concentration. Significantly higher FC extraction yield was obtained with longer sample incubation time for both methods (P = 0.019 EliATM Calprotectin; P < 0.001 fCAL® Turbo) and with increasing initial sample dilution for fCAL® Turbo method (P < 0.001). CONCLUSION: Preanalytical stool sample handling proved to be a crucial factor contributing to within- and between-FC assay variability. Standardization is urgently needed in order to assure comparable and reliable FC results.

The role of laboratory testing in detection and classification of chronic kidney disease: national recommendations.

Chronic kidney disease (CKD) is a common clinical condition with significant adverse consequences for the patient and it is recognized as a significant public health problem. The role of laboratory medicine in diagnosis and management of CKD is of great importance: the diagnosis and staging are based on estimation of glomerular filtration rate (eGFR) and assessment of albuminuria (or proteinuria). Therefore, the joint working group of the Croatian society of medical biochemistry and laboratory medicine and Croatian chamber of medical biochemists for laboratory diagnostics in CKD issued this national recommendation regarding laboratory diagnostics of CKD.Key factors for laboratories implementing the national guidelines for the diagnosis and management of CKD are:1. Ensure good communication between laboratory professionals and clinicians, such as nephrologists or specialists in general/family medicine,2. Ensure all patients are provided with the same availability of laboratory diagnostics,3. Ensure creatinine assays are traceable to isotope dilution mass spectrometry (IDMS) method and have minimal bias and acceptable imprecision,4. Select the appropriate GFR estimating formula. Recommended equation is the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD - EPI) equation,5. In reporting the key laboratory tests (creatinine, eGFR, urine albumin-to-creatinine ratio, urine protein-to-creatinine ratio) use the appropriate reporting units,6. Provide adequate information on limitations of creatinine measurement.The manuscript has been organized to identify critical points in laboratory tests used in basic laboratory diagnostics of CKD and is based on the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease.

Unusual pattern in haemoglobin electrophoresis in Croatian population: a case report.

Haemoglobinopathies are hereditary disorders of globin chain synthesis and are the most common inherited diseases worldwide. Haemoglobin E is a structural haemoglobin variant characteristic for South East Asian population. We present a rare and unusual finding of haemoglobin E detected in University Hospital Centre Zagreb by capillary zone electrophoresis. Detection of haemoglobin structural variant helped to avoid misdiagnosis of sideropenic anemia and thus potentially harmful therapeutic intervention. In today's European multiethnic population haemoglobinopathies are a public health issue and Croatian laboratory professionals should be aware of a possibility of finding an unusual haemoglobin pattern.

Laboratory diagnostics of chronic kidney disease in Croatia: state of the art.

INTRODUCTION: Early identification and management of chronic kidney disease (CKD) is highly cost-effective and can reduce the risk of kidney failure progression and cardiovascular disease. In 2014, the Joint Croatian Working Group (JCWG) for laboratory diagnostic of CKD on the behalf of Croatian society of medical biochemistry and laboratory medicine (CSMBLM) and Croatian chamber of medical biochemists (CCMB) conducted a survey across Croatian medical-biochemistry laboratories to assess the current practice in this area of laboratory medicine. The aim of this study was to present the data collected through the survey and to give insight about laboratory diagnostics of chronic kidney disease in Croatia. MATERIALS AND METHODS: An invitation to participate in the survey was sent to all Croatian medical-biochemistry laboratories (N=196). The questionnaire was designed in a form of questions and statements, with possible multiple answers, comprising 24 questions. RESULTS: The response rate was 80/196 (40.8%). 39 answers were from primary medical-biochemistry laboratories. 31/78 (0.40) laboratories measure creatinine with non-standardized method (uncompensated Jaffe method). 58/78 (0.74) of laboratories that measure creatinine do not report eGFR values. Similar number of laboratories (58/80, 0.73) do not measure urine albumin or protein. CONCLUSIONS: There is a large heterogeneity among Croatian laboratories regarding measuring methods, reporting units and reference intervals (cut-off values), both for creatinine and urine albumin or protein. The two key prerequisites for CKD screening, automatic reporting of eGFR and albuminuria or proteinuria assessment, are not implemented nationwide. There is a need for harmonization in laboratory diagnostics of CKD in Croatia.

Redefinition of gestational diabetes mellitus: implications for laboratory practice in Croatia.

An increasing prevalence of gestational diabetes has become a very challenging task in prenatal care worldwide. International Association of Diabetes and Pregnancy Study Groups (IADPSG) has recently issued recommendations on the diagnosis and classification of hyperglycaemia in pregnancy. These recommendations, the first to provide harmonised, evidence-based criteria for the diagnosis and classification of diabetes in pregnancy, are currently being discussed and accepted worldwide by the relevant authorities. As the acceptance of the proposed criteria has major implications for both clinical and laboratory settings, a concerted action towards necessary changes in practice has to be carefully planned and adjusted to national health-care specificities. IADPSG criteria have been strongly advocated by the Croatian Perinatology Society, resulting in a new strategy for the detection and diagnosis of hyperglycaemic disorders in pregnancy. To address the respective laboratory requirements, in April 2012, the Croatian Chamber of Medical Biochemists appointed a Working Group to provide a standardised procedure for the diagnosis of gestational diabetes, applicable to all laboratories involved in prenatal care, in both primary and specialised health-care facilities. In this paper we discuss key laboratory-related issues regarding succesful implementation of the IADPSG criteria in Croatia.

The quality of the extra-analytical phase of laboratory practice in some developing European countries and Mexico - a multicentric study.

BACKGROUND: This cross-sectional multicentric survey study aimed to assess the quality of the extra-analytical phase of laboratory activities in some developing European countries and Mexico. We assessed the quality of the extra-analytical practices in participating laboratories regarding the: a) sample acceptance criteria; b) phlebotomy procedures; c) test results reporting and d) recording non-conformities. METHODS: A survey was performed during the April-May 2009. A total of 15 clinical laboratories from the following countries were included: Bosnia, Croatia, Czech Republic, Hungary, Mexico, Poland, Portugal, Romania, Serbia and Ukraine. Questions were scored (scores from 1-4) and average scores was calculated for each category. RESULTS: The overall score for all respondents (n = 443) was 3.10 ± 0.33. The average score was 3.11 ± 0.56 for sample acceptance criteria, 2.76 ± 0.58 for phlebotomy and 3.34 ± 0.53, for test results reporting (F = 116.49; p < 0.001). Laboratory accreditation was associated with better practices and higher overall quality of the extra-analytical procedures (F = 16.62; p < 0.001). Moreover, the highest scores for sample acceptance criteria (F = 8.32; p < 0.001), phlebotomy procedures (F = 13.28; p < 0.001) and for reporting non-conformities (F = 33.62; p < 0.001) were observed for accredited laboratories or laboratories under preparation for accreditation. CONCLUSIONS: The overall quality of the extra-analytical practices in countries in this survey is not satisfactory. Phlebotomy practices are the most critical extra-analytical activity. Since laboratory accreditation was associated with better practices and higher overall quality of the extra-analytical procedures, we believe that the most significant improvement could be made by implementing the total quality management system and standardizing laboratory procedures.

Genotype frequencies of UDP-glucuronosyltransferase 1A1 promoter gene polymorphism in the population of healthy Croatian pre-scholars.

Increased serum bilirubin levels in patients with Gilbert syndrome (GS) are caused by reduction of hepatic activity of bilirubin glucuronosyltranferase to about 30% of normal. UGT1A1 genetic polymorphism with absent or very low bilirubin UDP-glucuronosyltransferase (B-UGT) activity is associated with Gilbert's syndrome (GS) and other hyperbilirubinemias. The genetic basis of GS is the insertion of two additional TA nucleotides (resulting in seven repeats of TA) in the TATAA box, present in proximal promoter of UGT1A1 gene. This study included 323 Croatian pre-scholars, including 164 boys and 159 girls. Statistical analysis showed significant difference for total bilirubin concentration between different genotypes (p < 0.001). Also, statistically significant difference for total bilirubin concentration was emphasized between genotypes 6/6 and 7/7 (p < 0.001) as well as 6/7 and 7/7 (p < 0.001). Higher total plasma bilirubin concentrations are significantly correlated with 7/7 genotype which is present in 9.8% of population studied.

N-phthaloyl-glycine-hydroxamic acid as serum iron chelator in rats.

The aim of this study was to investigate the activity of N-phthaloyl-glycine-hydroxamic acid (Phth-Gly-HA) as a new iron chelator in vivo to be used in iron overload diseases. After intraperitoneal application of Phth-Gly-HA to male rats (1 mg kg(-1) body mass) once a day for seven days, iron serum level decreased by 21%, whereas the iron value dropped by 32% in female rats (1.5 mg kg(-1) body mass). The results indicate that the tested substance has the ability to bind serum iron by complexation. Besides transferrin iron release, mobilization of ferritin iron is also possible.