New approach to standardization of D-dimer estimation using universal control materials

Abstract

The main problem in the D-dimer estimation in plasma is the almost complete lack of standardization at the production stage of laboratory equipment and reagents, calibrators, test systems, and control materials. In two cycles of interlaboratory comparisons (100 laboratories were included in the study) interlaboratory coefficient of variation reached 80 %. Method of determining normal values for the population, offered by manufacturers of reagents for each laboratory, is unacceptable due to the complexity of this work and its high cost. The aim of this study was to compare laboratory D-dimer determination in plasma samples of patients and control materials with the use of automated analysis techniques to improve the accuracy of the determination of this analyte in clinical practice without a set of reference values for groups of healthy individuals of different age and gender. Materials and methods: comparative analysis of results of D-dimer determination in plasma of healthy donors and patients undergoing treatment at the Institute of obstetrics, gynecology and reproductology n.a. D. O. Ott and clinics of the Medical university n.a. acad. I. P. Pavlov (St. Petersburg). Results: mathematical method of recalibration of laboratory equipment (methods) to compare the results of the D-dimer determination with two levels (low and high) of universal control material was proposed. It was determined that it is advisable to make the recalibration (multiply by a factor of comparability) of the results of D-dimer determination if there is a significant deviation of the coefficient of correlation from the value of 1.0.