Clinical application evaluation of chromogenic substrate assay in detecting coagulation factor Ⅷ activity / 中华检验医学杂志

ABSTRACT

Objective:To establish clinical detection of coagulation factor Ⅷ activity by chromogenic substrate assay and evaluate its clinical application.Methods:A total of 40 hemophilia Apatients, 20 acquired hemophilia A patients, 26 patients with positive lupus anticoagulant and 60 apparently healthy people were enrolled from January 2018 to May 2019 in Ruijin Hospital of Medical College, Shanghai Jiaotong University. According to Clinical and Laboratory Standards Institute(CLSI), the accuracy, within-run and between-run imprecision, lower detection limit, linear range, carryover rate, reference range, and reportable range of chromogenic substrate assay for detecting coagulation factor Ⅷ activity was evaluated, and compared with coagulation assay. The clinical application was evaluated by detecting F Ⅷ activity in acquired hemophilia A patients and patients with lupus anticoagulant by chromogenic substrate assay.Results:The results of two constant quality control products were within range provided by the manufacturer(the bias was 3.93%-6.79%). The within-run imprecision was 1.86%-2.06%(≤5%). The between-run imprecision was 4.83%-6.90%(≤15%). The chromogenic substrate assay had a good performance in sensitivity(CV=11.23%<20%). The recommended reference range was appropriate for our laboratory. The maximum dilution was 1∶16. The linear range was 5.00%-193.50% (a=1.0243, R 2=1.000). The clinical reportable range was 0.50%-387.00%. The method had a low carryover rate (0.04%). The chromogenic substrate assay had good consistency with coagulation assay in detecting coagulation factor Ⅷactivity (R 2=0.961) as well as the titer of FⅧ inhibitor(R 2=0.973).The difference of FⅧ activity in patients with lupus anticoagulant between these two assays was statistically significant(t=9.232,P<0.05). Conclusion:The chromogenic substrate assay has a good performance in clinical detection of coagulation factor Ⅷactivity with wider clinical application and less interference.