PB1004 - Clinical performance evaluation of two new Stago systems for protein C levels determination: sthemO PC Clot and sthemO PC Chrom on sthemO 301 analyzer.

Background: Venous thromboembolic disease is a multifactorial disease. Both acquired and inherited conditions account as risk factors for both a first and a recurrent thrombotic event. Antithrombin deficiency is rare but one of the most important inherited risk factor.
The prevalence of Protein C (PC) deficiency is estimated to be 0.2% in the general population and results in a relative risk of a first VTE episode between 4 and 6. There are several methods to measure PC: quantitative determination of PC antigen, PC clotting activity or PC chromogenic activity. New reagents, sthemO PC Clot and sthemO PC Chrom, have been designed to determine PC levels through clotting and chromogenic activity assays on a new equipment from Diagnostica Stago: sthemO 301.

Aims: The objective of this work was the validation of the performance of sthemO PC Clot and sthemO PC Chrom on sthemO 301 for their intended uses, by performing a comparison with STA®-Staclot Protein C and STA®-Stachrom Protein C on STA-R Max®.

Methods: Normal and pathologic Quality Controls (QCs) were tested at the beginning and at the end of each run during sample testing to validate the runs on both the instruments. The study populations for the method comparison studies are described in the table 1

Results: For sthemO PC Clot and sthemO PC Chrom coefficients of variation (CV) of QCs were between 3.3% and 6.6 % and between 2.8 and 5.9 % for STA®-Staclot Protein C and STA®-Stachrom Protein C. All the QC’s were within the acceptance criteria according to the GFHT “French hemostasis and thrombosis group” guidelines.
Results of comparison are described in Passing Bablok representations in the figure 1.

Conclusion(s): With all acceptance criteria met during the evaluation, sthemO PC clot and sthemO PC Chrom are validated for their intended purposes.