Biochemia Medica最新文献

Introduction: Autoverification (AV) is a postanalytical tool that uses algorithms to validate test results according to specified criteria. The Clinical and Laboratory Standard Institute (CLSI) document for AV of clinical laboratory test result (AUTO-10A) includes recommendations for laboratories needing guidance on implementation of AV algorithms. The aim was to design and validate the AV algorithm for biochemical tests.

Materials and methods: Criteria were defined according to AUTO-10A. Three different approaches for algorithm were used as result limit checks, which are reference range, reference range ± total allowable error, and 2nd and 98th percentile values. To validate the algorithm, 720 cases in middleware were tested. For actual cases, 3,188,095 results and 194,520 reports in laboratory information system (LIS) were evaluated using the AV system. Cohen's kappa (κ) was calculated to determine the degree of agreement between seven independent reviewers and the AV system.

Results: The AV passing rate was found between 77% and 85%. The highest rates of AV were in alanine transaminase (ALT), direct bilirubin (DBIL), and magnesium (Mg), which all had AV rates exceeding 85%. The most common reason for non-validated results was the result limit check (41%). A total of 328 reports evaluated by reviewers were compared to AV system. The statistical analysis resulted in a κ value between 0.39 and 0.63 (P < 0.001) and an agreement rate between 79% and 88%.

Conclusions: Our improved model can help laboratories design, build, and validate AV systems and be used as starting point for different test groups.

In laboratory medicine, mathematical equations are frequently used to calculate various parameters including bias, imprecision, measurement uncertainty, sigma metric (SM), creatinine clearance, LDL-cholesterol concentration, etc. Mathematical equations have strict limitations and cannot be used in all situations and are not open to manipulations. Recently, a paper "Bias estimation for Sigma metric calculation: Arithmetic mean versus quadratic mean" was published in Biochemia Medica. In the paper, the author criticized the approach of taking the arithmetic mean of the multiple biases to obtain a single bias and proposed a quadratic method to estimate the overall bias using external quality assurance services (EQAS) data for SM calculation. This approach does not fit the purpose and it should be noted that using the correct equation in calculations is as important as using the correct reagent in the measurement of the analytes, therefore before using an equation, its suitability should be checked and confirmed.

Hepatic cirrhosis is a major health problem across the world, causing high morbidity and mortality. This disease has many etiologies, yet the result of chronic hepatic injury is hepatic fibrosis causing cirrhosis and hepatocellular carcinoma, as the liver's architecture is progressively destroyed. While liver biopsy is currently the gold standard for fibrosis staging, it has significant disadvantages, leading to a growing interest in non-invasive markers. Direct biomarkers - hyaluronic acid, laminin, collagen type III N-peptide, type IV collagen and cholylglycine - are new and rarely applied in routine clinical practice. This is the case primarily because there is no general consensus regarding the clinical application and effectiveness of the individual biomarkers. The usage of these markers in routine clinical practice could be advantageous for patients with liver fibrosis, requiring a simple blood test instead of a biopsy. The former option would be especially attractive for patients who are contraindicated for the latter. This review summarizes recent findings on direct biomarkers of liver fibrosis and highlights their possible applications and potential benefit for liver fibrosis diagnostics and/or staging.

It is now generally accepted that laboratory errors or inaccurate results are mainly due to deficiencies in the pre-analytical phase. In this report, we describe the case of a 64-year-old male affected by a relapsing follicular lymphoma, who has been treated with chemotherapy through a central venous catheter (CVC). Four different samples were collected alternatively through peripheral venipuncture and CVC sampling. Unexpectedly, the samples collected from the two different sources showed contrasting results, with the presence of unusual macrophage-like cells in the samples obtained from CVC. It was later found that the CVC was displaced into the pleural space. This case report shows how the sampling process can sometimes influence test results and how it can help clinicians identify clinical conditions that have not yet manifested.

Introduction: Laboratory 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 methods: Working 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.

Results: Fifty-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).

Conclusion: This 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.

Introduction: Due to limitations in currently used methodologies, the widely acknowledged approach for quantifying M-protein (MP) is not available. If employed as a source of quantitative data, the immunosubtraction electropherogram (IS-EPG), a qualitative analysis of MP, has the potential to overcome known analytical issues. The aim of this study is to explore measured and derived variables obtained from immunosubtraction electropherogram as a tool for quantifying MP and to compare the derived results to currently available methods.

Materials and methods: Measurands were amplitudes of MP and albumin fractions. Assessed derived variables included also immunoglobulin (Ig) G, IgA, IgM and total protein data. Capillary electrophoresis was used for determination of MP (in % of total protein concentration, or concentration of MP in g/L) by perpendicular drop and tangent skimming method.

Results: Passing-Bablok analysis showed the most comparable results in D1Ig and D1nIg variables, and the largest discrepancies in AD1nIg and AD2nIg variables. The background presence had greater impact on D1nIg comparison results than did on D1Ig results. The contribution of albumin fraction data did not improve the comparability of the results. The coefficients of variation of derived variables were lower (maximum 3.1%) than those obtained by densitometric measurements, regardless of MP concentration, polyclonal background, or migration pattern (2.3-37.7%).

Conclusion: The amplitude of MP spike in IS-EPG is an valuable measurand to compute derived variables for quantifying MP. The most comparable results were achieved with the D1Ig variable. Patients with monoclonal gammopathy can benefit from increased precision employing an objective and background independent measurand, especially during longitudinal follow-up.

The acquired hemophilia A (AHA) is a life-threatening condition. The incidence of AHA is extremely low, which requires a multidisciplinary approach to diagnosis and treatment. This is case report of 73-year-old man who presented with AHA secondary to severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) pneumonia. The patient had extensive skin bleeding and hematomas. In the coagulation screening tests activated partial thromboplastin time (APTT) was prolonged with normal prothrombin time (PT), which was indication for further investigation. The APTT in a mixing study with normal plasma did not correct so clotting factors inhibitors were suspected. With signs of bleeding, extremely low factor VIII (FVIII) activity (2%) and presence of FVIII inhibitors, AHA was diagnosed and treatment initiated. Patient was treated with factor eight inhibitor bypassing agent (FEIBA) for three days, followed by long-term corticosteroid and cyclophosphamide therapy. Malignant and autoimmune diseases as the most common causes of AHA were ruled out. The patient had a good response to therapy with gradual normalization of APTT and FVIII activity. To the best of our knowledge, the present case is the first reported case of de novo AHA after SARS-CoV-2 pneumonia. The diagnosis of AHA should be suspected in a patient with bleeding into the skin and mucous membranes without a previous personal and family history of bleeding, and with isolated prolonged APTT. It is important to investigate any isolated prolongation of APTT in cooperation with clinical laboratory experts.

Introduction: The aim of the study was to determine the current state of laboratory's extra-analytical phase performance by calculating preanalytical and postanalytical phase quality indicators (QIs) and sigma values and to compare obtained data according to desired quality specifications and sigma values reported by The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Working Group - Laboratory errors and Patient Safety.

Materials and methods: Preanalytical and postanalytical phase data were obtained through laboratory information system. Rejected samples in preanalytical phase were grouped according to reasons for rejection and frequencies were calculated both monthly and for 2019. Sigma values were calculated according to "short term sigma" table.

Results: The number of rejected samples in laboratory was 643 out of 191,831 in 2019. Total preanalytical phase rejection frequency was 0.22%. According to the reasons for rejection, QIs and sigma values were: "Samples with excessive transportation time": 0.0036 and 5.47; "Samples collected in wrong container" 0.02 and 5.11. In December, QIs and sigma values were: "Samples with excessive transportation time": 0.01 and 5.34; "Samples collected in wrong container": 0.03 and 4.98. The postanalytical QIs and sigma values were: "Reports delivered outside the specified time": 0.34 and 4.21; "Turn around time of potassium": 56 minute and 3.84, respectively. There were no errors in "Critical values of inpatients and outpatients notified after a consensually agreed time".

Conclusions: Extra-analytical phase was evaluated by comparing it with the latest quality specifications and sigma values which will contribute to improving the quality of laboratory medicine.

Introduction: Systemic sclerosis (Ssc) is a multiorgan debilitating autoimmune disease that associates the triad: vascular involvement, tissue fibrosis and profound immune response alterations. Numerous previous studies focused on identification of candidate proteomic Ssc biomarkers using mass-spectrometry techniques and a large number of candidate Ssc biomarkers emerged. These biomarkers must firstly be confirmed in independent patient groups. The aim of the present study was to investigate the association of cytokeratin 17 (CK17), marginal zone B1 protein (MZB1) and leucine-rich α2-glycoprotein-1 (LRG1) with clinical and biological Ssc characteristics.

Material and methods: Serum CK17, MZB1 and LRG1 were assessed in samples of the available Ssc biobank comprising of samples from 53 Ssc patients and 26 matched age and gender controls.

Results: Circulatory CK17, LRG1 and MZB1 concentrations were increased in Ssc patients. Cytokeratin 17 is independently associated with Ssc disease activity. Patients with pulmonary fibrosis expressed higher LRG1 and MZB1 concentrations. Serum MZB1 concentrations were also associated with extensive skin fibrosis.

Conclusions: Serum CK17, MZB1 and LRG1 were confirmed biomarkers for Ssc. LRG1 seems a good biomarker for pulmonary fibrosis, while MZB1 is a good biomarker for extensive skin fibrosis. CK17 proved to be independently associated with Ssc disease severity, higher CK17 values being protective for a more active disease.