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Evaluation of D-dimer levels measured by different analytical methods in COVID-19 patients
Fatma Demet Arslan1, Banu Işbilen Başok2, Mustafa Terzioğlu2
1Department of Medical Biochemistry, University of Bakircay, School of Medicine.
Insights
Standardization of D-dimer testing is crucial for COVID-19 prognosis. This study compared D-dimer assays, finding immunoturbidimetric methods acceptable but recommending consistent use of the same assay system for monitoring COVID-19 patients.
Area of Science:
- Clinical Chemistry
- Biomarker Analysis
- COVID-19 Diagnostics
Background:
- D-dimer is a prognostic marker for COVID-19, but lack of test standardization presents clinical challenges.
- Variability in D-dimer results from different devices and methods can impact patient management.
Purpose of the Study:
- To compare the clinical and analytical performance of D-dimer assays using different kits and methods in COVID-19 patients.
- To evaluate the agreement and identify potential discrepancies between various D-dimer testing systems.
Main Methods:
- D-dimer levels were measured in 39 COVID-19 patients and 24 healthy individuals using immunoturbidimetric (Innovance D-DIMER on Sysmex CS-2500 and BCS XP) and enzyme-linked fluorescence (VIDAS D-Dimer Exclusion II on mini VIDAS) methods.
- Studies included precision, method comparison, and clinical performance evaluation.
Main Results:
- All systems demonstrated acceptable imprecision (CV ≤ 7.8%).
- Bias between Sysmex CS-2500 and BCS XP was within acceptable limits (<15.5%), while bias with mini VIDAS was higher (>19%).
- Correlation coefficients ranged from 0.89-0.98, with near-perfect agreement between Sysmex and BCS XP for specific thresholds.
Conclusions:
- The immunoturbidimetric method shows satisfactory agreement and can be an alternative to the enzyme-linked fluorescent method for venous thromboembolism thresholds.
- Consistent use of the same D-dimer assay system is recommended for monitoring COVID-19 patients to ensure reliable results.
Abstract:
Clinicians experience some challenges due to the lack of standardization of test, although D-dimer is a prognostic marker for COVID-19. We compared the clinical and analytical performances of D-dimer results obtained from different devices, kits and methods in patients with a diagnosis of COVID-19. Thirty-nine patients with a diagnosis of COVID-19 and 24 healthy individuals were included in the study. D-dimer levels were measured with Innovance D-DIMER kit (immunoturbidimetric method) on Sysmex CS-2500 and BCS XP and VIDAS D-Dimer Exclusion II kit (enzyme-linked fluorescence method) on mini VIDAS. The studies of precision, method comparison and clinic performance were performed. The variation coefficients in all systems were within the acceptable imprecision (7.8%). Bias%(12.5%) between BCS XP and Sysmex CS-2500 was lower than the acceptable Bias%(15.5%). Bias% values (19.2% and 33.3%, respectively) between Mini VIDAS with BCS XP and Sysmex CS-2500 were higher than the acceptable Bias%. The correlation coefficients among all systems were 0.89-0.98. For 500 ng/ml FEU, there was almost perfect agreement between BCS XP and Sysmex CS-2500, a moderate agreement between Mini VIDAS and BCS XP and Sysmex CS-2500. The cut-off values for distinguishing between individuals with and withoutCOVID-19 were Mini VIDAS, Sysmex CS-2500 and BCS XP 529, 380 and 390 ng/ml FEU, respectively. The immunoturbidimetric method can be used as an alternative to the enzyme-linked fluorescent method because of satisfactory agreement at the different thresholds proposed for venous thromboembolism. However, it is recommended to follow up COVID-19 with the D-dimer results obtained by the same assay system.
