Professional paper

Determination of D-dimer by different quantitative assays - A harmonization exercise

Mojca Stegnar ; Department of Vascular Diseases, University Medical Centre Ljubljana, Ljubljana, Slovenia
Mojca Božič ; Department of Vascular Diseases, University Medical Centre Ljubljana, Ljubljana, Slovenia

Abstract

Background: D-dimer determined by different assays shows considerable variability due to lack of standardization. We describe a harmonization exercise performed in an attempt to diminish this variability using plasma samples with high D-dimer concentration.
Materials and methods: Five laboratories participated with several different quantitative D-dimer assays: Vidas D-dimer Exclusion (Biomerieux), Auto-Dimer (Biopool), D-dimer Plus, Acute Care D-dimer (both Dade Behring) and Hemosil D-Dimer (Instrumentation Laboratory). For harmonization a set of six plasmas was prepared: normal pooled plasma and samples A-E, prepared by mixing normal pooled plasma with increasing parts (1,2,3,8 and 14.7) of patient pooled plasma with a high D-dimer concentration. For validation 15 plasma samples from patients with venous thromboembolism were utilized.
Results: A reference regression line through the mean values of D-dimer in samples A-E was calculated and used to harmonize the results of the 15 validation samples. After harmonization the coefficients of variation improved considerably from 89% to 19% (mean values) for validation samples with high D-dimer concentration. For validation samples with low D-dimer concentration (normal or around cut-off) coefficients of variation even increased from a mean value of 86% before harmonization to a mean value of 224% after harmonization.
Conclusions: The harmonization procedure considerably decreased variability between different D-dimer assays in samples with a high D-dimer concentration. However, for samples with D-dimer concentration around cut-off, which is critical for clinical application, no improvement was observed.

Keywords

D-dimer; harmonization; validation

Hrčak ID:

24162

URI

https://hrcak.srce.hr/24162

Publication date:

5.6.2008.

Article data in other languages: croatian

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