Browsing by Author "Zengi, Oguzhan"

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Measuring the Impact: Severity of Harm From Laboratory Errors in 195 Tests
(Oxford Univ Press inc, 2024) Cubukcu, Hikmet Can; Cihan, Murat; Alp, Hamit Hakan; Bolat, Serkan; Zengi, Oguzhan; Ucar, Kamil Taha; Serdar, Muhittin Abdulkadir
Objectives This study aimed to objectively assess the potential severity of harm associated with erroneous results in 195 laboratory tests by surveying 514 specialist physicians and medical biochemistry experts.Methods The survey obtained participants' (75 medical biochemists, 439 clinicians) opinions on severity of harm for the erroneous results of 195 tests. The comprehensive list of errors and their effects on test results were obtained from the literature, and then matched with severity of harm scores, from 1 (negligible effect) to 5 (life-threatening injury/death), obtained from the survey responses.Results Participants perceived tests such as cardiac biomarkers, blood gases, coagulation parameters (activated partial thromboplastin time, prothrombin time, international normalized ratio, and dimerized plasmin fragment D), critical ions (potassium, sodium), toxic trace elements (lead, mercury), and specific serum drug levels (lithium, digoxin) to have a greater potential for patient harm in case of errors. Medical biochemistry specialists assigned higher severity scores to some laboratory tests, including total bilirubin, pseudocholinesterase, platelet indices, and some drug levels (cyclosporine, methotrexate, vancomycin).Conclusions A substantial agreement (91%) was observed between medical biochemists and clinicians in terms of the most frequently chosen severity of harm score. The study provided objective severity scores and identified high-risk tests for targeted quality improvement.
A Proof-Of Practical Approach for Achieving Equivalent Results From Non-Harmonized Measurement Methods While Awaiting Harmonization: the Ca 125 Example
(Elsevier, 2025) Cubukcu, Hikmet Can; Zengi, Oguzhan; Alp, Hamit Hakan; Ucar, Kamil Taha; Cihan, Murat; Thelen, Marc; Panteghini, Mauro
Background: Laboratory test results are crucial for clinical decisions, yet inconsistencies arise when measurements are not harmonized due to the lack of suitable higher-order references. This study introduces an approach to improve result comparability across different measurement systems, applicable until full metrological harmonization of the measurand is achieved. Methods: A linear transformation formula was developed, utilizing the 2.5th and 97.5th percentiles of data from source and target methods, to adjust source method results. The feasibility of this formula was tested using carbohydrate antigen 125 (CA 125) data from two commercial assays provided by Roche Diagnostics and Abbott Diagnostics. Method comparison statistics, including difference plots and Passing-Bablok regression, were used to evaluate the transformation's effectiveness before and after adjustment. A web application, "Result Transformer," was developed to facilitate the application of the transformation process. Results: Prior to transformation, the median relative difference between the Roche and Abbott CA 125 assays was 37.7% (95% CI: 34.5-40.8%), exceeding acceptable bias. Passing-Bablok regression yielded a slope of 1.450 (95% CI: 1.400-1.485) and an intercept of -0.83 kU/L (95% CI: -1.50 to -0.29). After adjustment using the proposed approach, the median relative difference decreased to 6.0% (95% CI: 4.3-7.7%), falling within the desirable acceptable bias goal. The slope and intercept of the regression equation improved to 1.075 (95% CI: 1.039-1.102) and -0.12 kU/L (95% CI: -0.71 to 0.19), respectively. Conclusion: The proposed transformation method effectively improved the comparability of results from different assays, permitting a more consistent test result interpretation during patient follow-up.