Development of a novel automated screening method for detection of FVIII Inhibitors

作者：Evans M S^*; Donaldson K J; Eyster M E

来源：International Journal of Laboratory Hematology, 2017, 39(2): 185-190.

DOI：10.1111/ijlh.12601

• FVIII
• hemophilia
• inhibitors
• automated laboratory screening
• coagulation inhibitors

IntroductionFactor VIII activity is routinely determined by measuring the activated partial thromboplastin time (aPTT) of a patient plasma sample and determining percent activity from a standard curve. To maximize the detection of a clotting factor inhibitor, a subjective assessment of parallelism of a patient curve compared with a standard curve is performed. We developed and validated an automated objective method to assess parallelism as a rapid screening tool for detection of an inhibitor to factor VIII during routine FVIII assays.
MethodsWe performed FVIII assays on a subset of FVIII-deficient patients with hemophilia A with and without inhibitors. Utilizing a ratio of the slopes from parallelism curves obtained by an independent Microsoft excel program in patients compared with a normal standard curve, we determined a cutoff ratio predictive for presence of an inhibitor.
ResultsA cutoff ratio of patient to control slopes of <0.45 for the detection of an inhibitor to FVIII was 100% sensitive and 91.6% specific, with a positive predictive value of 92.3% and a negative predictive value of 100%.
ConclusionUtilizing a ratio of the slopes from parallelism curves in patients with and without an inhibitor, we developed and validated a rapid, automated, and objective method to assess parallelism as an added screening tool for detection of an inhibitor to factor VIII during routine FVIII assays on a STAGO-based coagulation platform. This simple automated method has the potential to detect inhibitors to other clotting factors.

• 出版日期2017-4