Araştırma Çıktıları
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Item Utilization of biological variation data in the interpretation of laboratory test results - survey about clinicians' opinion and knowledge(CROATIAN SOC MEDICAL BIOCHEMISTRY \& LABORATORY MEDICINE, 2021-01-01) Emre, Humeyra Ozturk; Karpuzoglu, Fatma Hande; Coskun, Cihan; Sezer, Ebru Demirel; Ozturk, Ozlem Goruroglu; Ucar, Fatma; Cubukcu, Hikmet Can; Arslan, Fatma Demet; Deniz, Levent; Senes, Mehmet; Serteser, Mustafa; Yazici, Cevat; Yucel, Dogan; Coskun, AbdurrahmanIntroduction: To interpret test results correctly, understanding of the variations that affect test results is essential. The aim of this study is: 1) to evaluate the clinicians' knowledge and opinion concerning biological variation (BV), and 2) to investigate if clinicians use BV in the interpretation of test results. Materials and methods: This study uses a questionnaire comprising open-ended and close-ended questions. Questions were selected from the real-life numerical examples of interpretation of test results, the knowledge about main sources of variations in laboratories and the opinion of clinicians on BV. A total of 399 clinicians were interviewed, and the answers were evaluated using a scoring system ranked from A (clinician has the highest level of knowledge and the ability of using BV data) to D (clinician has no knowledge about variations in laboratory). The results were presented as number (N) and percentage (\%). Results: Altogether, 60.4\% of clinicians have knowledge of pre-analytical and analytical variationsItem The European Biological Variation Study (EuBIVAS): Biological Variation Data for Coagulation Markers Estimated by a Bayesian Model(OXFORD UNIV PRESS INC, 2021-01-01) Aarsand, Aasne K.; Kristoffersen, Ann Helen; Sandberg, Sverre; Stove, Bard; Coskun, Abdurrahman; Fernandez-Calle, Pilar; Diaz-Garzon, Jorge; Guerra, Elena; Ceriotti, Ferruccio; Jonker, Niels; Roraas, Thomas; Carobene, Anna; Chem, European Federation ClinicalBACKGROUND: For biological variation (BV) data to be safely used, data must be reliable and relevant to the population in which they are applied. We used samples from the European Biological Variation Study (EuBIVAS) to determine BV of coagulation markers by a Bayesian model robust to extreme observations and used the derived within-participant BV estimates {[}CVP(i)] to assess the applicability of the BV estimates in clinical practice. METHOD: Plasma samples were drawn from 92 healthy individuals for 10 consecutive weeks at 6 European laboratories and analyzed in duplicate for activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen, D-dimer, antithrombin (AT), protein C, protein S free, and factor VIII (FVIII). A Bayesian model with Student t likelihoods for samples and replicates was applied to derive CVP(i) and predicted BV estimates with 95\% credibility intervals. RESULTS: For all markers except D-dimer, CVP( i) were homogeneously distributed in the overall study population or in subgroups. Mean within-subject estimates (CVI) were <5\% for APTT, PT, AT, and protein S free, <10\% for protein C and FVIII, and <12\% for fibrinogen. For APTT, protein C, and protein S free, estimates were significantly lower in men than in women <= 50 years. CONCLUSION: For most coagulation markers, a common CVI estimate for men and women is applicable, whereas for APTT, protein C, and protein S free, sex-specific reference change values should be applied. The use of a Bayesian model to deliver individual CVP(i) allows for improved interpretation and application of the data.Item The European Biological Variation Study (EuBIVAS): weekly biological variation of cardiac troponin I estimated by the use of two different high-sensitivity cardiac troponin I assays(WALTER DE GRUYTER GMBH, 2020-01-01) Ceriotti, Ferruccio; Diaz-Garzon Marco, Jorge; Fernandez-Calle, Pilar; Maregnani, Alessio; Aarsand, Aasne K.; Coskun, Abdurrahman; Jonker, Niels; Sandberg, Sverre; Carobene, Anna; Chem, European Federation ClinicalBackground: Cardiac troponins (cTn) are specific markers for cardiac damage and acute coronary syndromes. The availability of new high-sensitivity assays allows cTn detection in healthy people, thus permitting the estimation of biological variation (BV) of cTn. The knowledge of BV is important to define analytical performance specifications (APS) and reference change values (RCVs). The aim of this study was to estimate the within- and between-subject weekly BV (CVI, CVG) of cTnI applying two high-sensitivity cTnI assays, using European Biological Variation Study (EuBIVAS) specimens. Methods: Thirty-eight men and 53 women underwent weekly fasting blood drawings for 10 consecutive weeks. Duplicate measurements were performed with Singulex Clarity (Singulex, USA) and Siemens Atellica (Siemens Healthineers, Germany). Results: cTnI was measurable in 99.4\% and 74.3\% of the samples with Singulex and Atellica assays, respectively. Concentrations were significantly higher in men than in women with both methods. The CVI estimates with 95\% confidence interval (CI) were for Singulex 16.6\% (15.6-17.7) and for Atellica 13.8\% (12.7-15.0), with the observed difference likely being caused by the different number of measurable samples. No significant CVI differences were observed between men and women. The CVG estimates for women were 40.3\% and 36.3\%, and for men 65.3\% and 36.5\% for Singulex and Atellica, respectively. The resulting APS and RCVs were similar for the two methods. Conclusions: This is the first study able to estimate cTnI BV for such a large cohort of well-characterized healthy individuals deriving objective APS and RCV values for detecting significant variations in cTnI serial measurements, even within the 99th percentile.Item Determining biological variation of serum parathyroid hormone in healthy adults(CROATIAN SOC MEDICAL BIOCHEMISTRY \& LABORATORY MEDICINE, 2019-01-01) Ercan, Mujgan; Akbulut, Emis Deniz; Avci, Esin; Yucel, Cigdem; Oguz, Esra Firat; Turhan, Turan; Serdar, MuhittinIntroduction: Measurement of parathyroid hormone (PTH) is essential in the investigation and management of calcium metabolism disorders. To assess the significance of any assay result when clinical decision making biological variation (BV) of the measurand must be taken into consideration. The aim of the present study is determining the BV parameters for serum PTH. Materials and methods: Blood samples were taken at weekly intervals from 20 healthy subjects for ten weeks in this prospective BV study. Serum ``intact PTH{''} concentrations were measured with electrochemiluminescence method. Biological variation parameters were estimated using the approach proposed by Fraser. Results: The values of within-subject biological variation (CVI), between-subject biological variation (CVG), analytical variation (CVA), reference change value (RCV) and individuality index (II) for serum PTH were 21.1\%, 24.9\%, 3.8\%, 59.4\% and 0.8\%, respectively. Within-subject biological variation and CVG were also determined according to gender separatelyItem Biological variation and reference change value data for serum copper, zinc and selenium in Turkish adult population(WALTER DE GRUYTER GMBH, 2021-01-01) Bal, Ceylan; Erdogan, Serpil; Gok, Gamze; Nural, Cemil; Ozbek, Betul; Ercan, Mujgan; Serdar, Muhittin; Erel, OzcanObjectives: Calculation of biological variation (BV) components is very important in evaluating whether a test result is clinically significant. The aim of this study is to analyze BV components for copper, zinc and selenium in a cohort of healthy Turkish participants. Methods: A total of 10 serum samples were collected from each of the 15 healthy individuals (nine female, six male), once a week, during 10 weeks. Copper, zinc and selenium levels were analyzed by atomic absorption spectrometer. BV parameters were calculated with the approach suggested by Fraser. Results: Analytical variation (CVA), within-subject BV (CVI), between-subject BV (CVG) values were 8.4, 7.1 and 4.3 for copper