Search

IntroductionLaboratory plays important part in screening, diagnosis, and management of thyroid disorders. The aim of this study was to estimate current laboratory preanalytical, analytical and postanalytical practices and policies in Croatia. Materials and methodsWorking Group for Laboratory Endocrinology of the Croatian Society of Medical Biochemistry and Laboratory Medicine designed a questionnaire with 27 questions and statements regarding practices and protocols in measuring thyroid function tests. The survey was sent to 111 medical biochemistry laboratories participating in external quality assurance scheme for thyroid hormones organized by Croatian Centre for Quality Assessment in Laboratory Medicine. Data is presented as absolute numbers and proportions. ResultsFifty-three participants returned the questionnaire. Response rate varied depending on question, yielding a total survey response rate of 46-48%. All respondents perform thyroid stimulating hormone (TSH). From all other thyroid tests, most performed is free thyroxine (37/53) and least TSH-stimulating immunoglobulin (1/53). Laboratories are using nine different immunoassay methods. One tenth of laboratories is verifying manufacturer’s declared limit of quantification for TSH and one third is verifying implemented reference intervals for all performed tests. Most of laboratories (91%) adopt the manufacturer’s reference interval for adult population. Reference intervals for TSH are reported with different percentiles (90, 95 or 99 percentiles). ConclusionThis survey showed current practices and policies in Croatian laboratories regarding thyroid testing. The results identified some critical spots and will serve as a foundation in creating national guidelines in order to harmonize laboratory procedures in thyroid testing in Croatia.

In the final phase of clot formation, fibrinogen constitutes frame, whereas factor XIII (FXIII) active form is responsible for the covalent cross-linking of fibrin fibres and plasmin inhibitor (PI), thus contributing to clot stability. It could be expected that any change of coagulation factors' structure affects the clot formation and modulates the atherothrombotic risk. The aim was to determine the frequency of four single nucleotide polymorphisms: (We performed the unrelated case-control association study on the consecutive sample of patients 18 years old, who had undergone coronary angiography for investigation of chest pain and suspected CAD. The cases were patients with confirmed CAD (N=201), and the controls were the subjects with no CAD (N=119). Samples were genotyped using PCR-RFLP analysis.Observed frequencies of the rare alleles of Thr312Ala FGA, 10034CT FGG, Leu564Pro FXIII-A and Arg6Trp PI polymorphisms were 21%, 17%, 14%, 20%, respectively. Patients with 10034CT FGG CC genotype had 3.5 times (95% CI 1.02-12.03) higher adjusted odds for CAD than patients with 10034CT FGG TT genotype. Patients with Arg6Trp PI CC genotype had 3.86 times (95% CI 1.23-12.12) higher odds for CAD than patients with Arg6Trp PI TT genotype. It seems that those genotype-related higher odds are also male-gender related. No difference was observed regarding any other investigated polymorphism.Our finding suggests that 10034CT FGG and Arg6Trp PI are associated with CAD.U završnoj fazi stvaranja ugruška fibrinogen čini okvir, dok je aktivni oblik faktora XIII (FXIII) odgovoran za kovalentno umrežavanje vlakana fibrina i inhibitora plazmina (PI), doprinoseći tako stabilnosti ugruška. Moglo bi se očekivati da svaka promena strukture faktora koagulacije utiče na stvaranje ugruška i modulira rizik od aterotrom - bota. Cilj je bio da se odredi frekvencija četiri pojedinačna nukleotidna polimorfizma: (I) AG u kodonu 312 gena a-lanca fibrinogena (rs6050, Thr312AlaFGA), (II) CT na položaju 10034 3' netransliranog regiona u genu g-lanca fibrinogena (rs2066865, 10034CTFGG), (III) CT u kodonu 564 gena podjedinice FXIII-A (rs5982, Pro564LeuFXIII-A), i (IV) CT u kodonu 6 gena inhibitora plazmina (rs2070863, Arg6TrpPI) kod hrvatskih pacijenata, i njihovu povezanost sa koronarnom arterijskom bolešću (CAD).Obavljeno je nepovezano istraživanje slučajeva i kontrola na uzastopnom uzorku pacijenata sa 18 i više godina koji su bili podvrgnuti koronarnoj angiografiji radi ispitivanja bola u grudima i sumnje na CAD. Slučajevi su bili pacijenti sa potvrđenom CAD (N = 201), a kontrolna grupa su bili oni koji nisu imali CAD (N = 119). Genetska konstrukcija uzoraka istražena je pomoću PCR-RFLP analize.Posmatrane frekvencije retkih alela Thr312Ala FGA, 10034 CT FGG, Leu564Pro FXIII-A i Arg6Trp PI polimorfizma bile su, redom, 21%, 17%, 14%, 20%. Pacijenti sa 10034 CT FGG CC genotipom imali su 3,5 puta (95% CI 1,02-12,03) veće prilagođene izglede za dobijanje CAD u odnosu na pacijente sa 10034 CT FGG TT genotipom. Pacijenti sa Arg6Trp PI CC genotipom imali su 3,86 puta (95% CI 1,23-12,12) veće izglede za CAD u odnosu na pacijente sa Arg6Trp PI TT genotipom. čini se da ti veći izgledi vezani za genotip takođe imaju veze i sa muškim polom. Nije uočena razlika u odnosu na bilo koji drugi istraženi polimorfizam.Dobijeni rezultati ukazuju na to da su 10034 CT FGG i Arg6Trp PI povezani sa CAD.

European Union (EU) Directive 2013/55/EC (The Recognition of Professional Qualifications) allows Member States to decide on a common set of minimum knowledge, skills and competences that are needed to pursue a given profession through a Common Training Framework. To be adopted the framework must combine the knowledge, skills and competences of at least one third of the Member States. Professionals who have gained their qualifications under a Common Training Framework will be able to have these recognised automatically within the Union. The backbone of the European Federation of Clinical Chemistry and Laboratory Medicine’s (EFLM) proposed Common Training Framework for non-medical Specialists in Laboratory Medicine is outlined here. It is based on an Equivalence of Standards in education, training, qualifications, knowledge, skills, competences and the professional conduct associated with specialist practice. In proposing the recognition of specialist practice EFLM has identified 15 EU Member States able to meet Equivalence and in whom the profession and/or its training is regulated (an additional EU Commission requirement). The framework supports and contributes to the Directive’s enabling goals for increasing professional mobility, safeguarding consumers and ensuring a more equitable distribution of skills and expertise across the Member States. It represents EFLM’s position statement and provides a template for professional societies and/or competent authorities to engage with the EU Commission.

Introduction: The aim of this study was to examine whether the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) could be applied to Croatian children and adolescents. Materials and methods: A total of 295 outpatient healthy children and adolescents of age 1 to 18 were selected using the direct a posteriori sampling method. According to current guidelines, 20 samples were tested for each of a total of 51 reference intervals for ferritin, cortisol, dehydroepiandrosterone sulfate, follicle stimulating hormone, lutein stimulating hormone, prolactin, progesterone, sex hormone binding globulin, thyroid stimulating hormone, total testosterone, total thyroxine and total triiodothyronine. Serum samples were analysed on the Beckman Coulter DxI600 immunoassay analyser by chemiluminescence immunoassay method. A reference interval was adopted if < 10% of the results fall outside CALIPER reference interval range. For analytes in which this criterion is not met in the first set of samples, a new set of 20 samples were collected. Results: After the first set of measurements, 96% of all tested reference intervals were adopted for use. The additional sets of 20 reference subjects were tested for only two reference intervals; follicle stimulating hormone for female aged 1 to 9 years, and irrespective of the gender, sex hormone binding globulin for children aged 8 to 11 years. All results of additional samples were within the specified interval limits. Conclusions: CALIPER reference intervals for ferritin and 11 hormones defined for Beckman Coulter DxI600 immunoassay analyser can be implemented into the Croatian laboratories and clinical practice.

The sweat test (ST) is a cornerstone in the diagnosis of cystic fibrosis (CF), together with newborn screening and genetic testing. However, the performance of the ST can depend on the operator's skill, so several international guidelines have been published to standardise the ST, but inconsistencies remain. The joint Working Group for ST Standardisation (WG STS) of the Croatian Society of Medical Biochemistry and Laboratory Medicine, in association with cistic fybrosis health professional and the Cistic Fibrosis Centre for Paediatrics and Adults, have issued National Guidelines for the Performance of the Sweat Test in order to ensure consistency in ST performance and accuracy of reported results. Many of the standards were taken from the 2nd Edition of the UK Guidelines for Performance of the ST for the Diagnosis of CF, while others were taken from independent consensus statements from the WG STS based on local ST equipment and practices. The standards cover every step of the ST, from the indications for testing to reporting of results and their interpretation, including the analytical phase and quality control. In addition, National Guidelines include appendices with practical examples in order to aid implementation of the recommendations in routine practice. Croatian Society of Medical Biochemistry and Laboratory Medicine.

Introduction: Activated partial thromboplastin time (aPTT) is determined and reported as clotting time in seconds aPTT(s), but it is presumed that reporting results as patient-to- normal clotting time ratio, aPTT(r), could minimize within- laboratory variability. The aim of study was to investigate differences in reporting aPTT results that can affect comparability of the results among Croatian laboratories and suggest further steps for its harmonization. Materials and methods: The questionnaire on aPTT reporting practice was distributed to 83 laboratories through Survey Monkey application in March 2019 as the part of the first regular round of Croatian Centre for Quality Assessment in Laboratory Medicine proficiency testing. Results: The survey response rate was 0.49. Majority of laboratories report aPTT results as both, seconds and ratio. Participants reported use of 23 different aPTT(s) reference intervals along with 17 different combinations of reagent/coagulometer and 25 aPTT(s) denominators of different origin for aPTT(r) calculation. Despite the same aPTT(s) results, the use of different denominators caused a dispersion of aPTT(r) results that can lead to exceeding external quality assessment performance criteria of 7%, particularly when results were compared for the same reagent group only. By applying aPTT(s) reference interval mean as denominator for calculation of aPTT(r) reference interval better concordance to harmonized one was obtained (17 vs. 27 ; χ2 = 3.972 ; P = 0.046). Conclusion: In order to improve comparability of the results, laboratories are advised to use mean of aPTT(s) reference interval as denominator for aPTT(r) calculation. Type of coagulometer need to be considered when evaluating aPTT proficiency test results and its currently acceptable limit of performance evaluated accordingly.

Background Although Immulite®2000XPi (Siemens) allergy testing is routinely used in laboratories worldwide; a well-designed comprehensive third-party verification of its analytical performance has not yet been published. Our aim was to verify stability, precision and reference intervals for total and some frequent specific IgEs, test trueness for several most common allergens and assess the comparability of fluorescent- and chemiluminescent-enzyme immunoassay for total IgE. Methods Verification was based on EP15-A3, EP9-A3 and EP28-A3c CLSI guidelines. Stability was tested on serum pools stored at 2–8 °C, during 7 days. Manufacturer’s reference intervals were verified for children and adults. Acceptance criteria were based on manufacturer specifications and national External Quality Assessment provider data. Results Samples for total IgE analysis were stable at 2–8 °C for 7 days. Precision was within manufacturer’s specifications for most of tested allergens, except for total IgE (92.5 kIU/L, CVs 5.6% and 7.6%) and w1 (9.3 kU/L, CV = 5.9%). Bland-Altman plot revealed statistically significant constant (−32.4 kIU/L) and proportional bias (−20.2%) for total IgE between two methods. Passing Bablok showed statistically but not clinically significant biases between two Immulite analyzers for betula verrucosa (constant and proportional), house dust mite and egg white allergens (proportional). For adults and children, total IgE results were within reference intervals declared by Siemens. Conclusions Immulite®2000XPi assay has acceptable precision and trueness. Samples for total IgE are stable even longer than declared by the manufacturer. Declared reference intervals can safely be adopted for both adult and children population in our laboratory. Fluorescent- and chemiluminescent-enzyme immunoassay results of total IgE are not comparable.

Introduction: Variability among manufacturers of urine dipsticks, respective to their accuracy and measurement range, may lead to diagnostic errors and thus create a serious risk for the patient. Our aims were to determine the level of agreement between 12 most commonly used urine dipsticks in Croatia, examine their accuracy for glucose and total protein and to test their repeatability. Materials and methods: A total of 75 urine samples were used to examine comparability and accuracy of 12 dipstick brands (Combur 10 TestM, ChoiceLine 10, Combur 10 TestUX, ComboStik 10M, ComboStik 11M, CombiScreen 11SYS, CombiScreen 10SL, Combina 13, Combina 11S, Combina 10M, UriGnost 11, Multistix 10SG). Agreement between each dipstick and the reference (Combur 10 TestM) was expressed as kappa coefficient (acceptable κ ≥ 0.80). Accuracy for glucose and total protein was tested by comparison with quantitative measurements on analysers: AU400 (Beckman Coulter, USA), Cobas 6000 c501 (Roche Diagnostics, Germany) and Architect plus c4000 (Abbott, USA). Repeatability was assessed on 20 replicates (acceptable > 90%). Results: Best agreement was achieved for glucose, total protein and nitrite (11/11, k > 0.80) and the lowest for bilirubin (5/5, k < 0.60). Sensitivities for total protein were 41-75% (AU400) and 56-92% (Cobas and Architect); while specificities were 41-75% (AU400, Cobas, Architect). Dipsticks’ sensitivity and specificity for glucose were 68-98%. Most of the dipsticks showed unacceptable repeatability (6/12, < 90%) for one parameter, most prominently for pH (3/12, < 90%). Conclusions: Most commonly used dipsticks in Croatia showed low level of agreement between each other. Moreover, their repeatability varies among manufacturers and their accuracy for glucose and proteins is poor.

Introduction: In line with the national recommendations, Croatian medical laboratories report urine test strip qualitative analysis results using a categorized scale with defined number of categories. Since concentration ranges for measured analytes have not been provided by national professional authority, it is up to the laboratories to define their own categories. The aim of study was to assess the comparability of concentrations assigned to different categories used in reporting the results of dipstick urinalysis in Croatian laboratories. Material and methods: A questionnaire was e-mailed to all Croatian medical laboratories (N = 195). They were asked to provide the number of categories and respective concentrations for each parameter. Data were described as numbers and percentages. Values above the upper reference range limit, which were assigned as normal and/or trace category, were considered as false negative. Results: Response rate was 71% (139/195). Seventy percent (98/139) of laboratories report their results with either higher (77/98; 79%) or lower (2/98; 2%) number of categories, relative to the national recommendation, whereas 19/98 (19%) report their results as concentrations. Great heterogeneity of reporting categories was observed. Multiple categories were assigned to same concentrations and there was a large overlap of concentrations for most categories. Considerable proportion of laboratories reported false negative results for ketones (42%), leukocytes (30%) and glucose (21%). Conclusions: The concentrations assigned to categories used to report the results of dipstick urinalysis are not comparable among Croatian medical laboratories. There is an urgent need for harmonization and standardization of reporting the results of urine dipstick analysis in Croatia.

Background: Laboratory evaluation through external quality assessment (EQA) schemes is often performed as ‘peer group’ comparison under the assumption that matrix effects influence the comparisons between results of different methods, for analytes where no commutable materials with reference value assignment are available. With EQA schemes that are not large but have many available instruments and reagent options for same analyte, homogenous peer groups must be created with adequate number of results to enable satisfactory statistical evaluation. We proposed a multivariate analysis of variance (MANOVA)-based test to evaluate heterogeneity of peer groups within the Croatian EQA biochemistry scheme and identify groups where further splitting might improve laboratory evaluation. Methods: EQA biochemistry results were divided according to instruments used per analyte and the MANOVA test was used to verify statistically significant differences between subgroups. The number of samples was determined by sample size calculation ensuring a power of 90% and allowing the false flagging rate to increase not more than 5%. When statistically significant differences between subgroups were found, clear improvement of laboratory evaluation was assessed before splitting groups. Results: After evaluating 29 peer groups, we found strong evidence for further splitting of six groups. Overall improvement of 6% reported results were observed, with the percentage being as high as 27.4% for one particular method. Conclusions: Defining maximal allowable differences between subgroups based on flagging rate change, followed by sample size planning and MANOVA, identifies heterogeneous peer groups where further splitting improves laboratory evaluation and enables continuous monitoring for peer group heterogeneity within EQA schemes.