ASSESSMENT OF ACTIVATED PROTEIN-C RESISTANCE USING A NEW AND RAPID VENOM-BASED TEST - STA STACLOT APC-R

Activated protein C (APC) resistance is related to a single point muta tion in the factor V gene (FV:Q(506)) and appears to be the most commo n inherited risk factor for venous thromboembolism. A reliable screeni ng test is therefore useful. We aimed to evaluate a new APC resistance test, on the basis of the procoagulant activity present in one snake venom of a crotalidae family: STA Staclot APC-R. We studied 36 consecu tive patients with an acute deep venous thrombosis (DVT) confirmed by compression ultrasonography and carrying the FV:Q(506) allele, assesse d by DNA analysis, 103 of their family members and 35 consecutive pati ents with a proven DVT but who did not carry the FV:Q(506) allele. Blo od samples were collected within 24 h of admission for the DVT cases a nd on the day of medical registration for the family members. Tests we re performed blind. The STA Staclot APC-R test, using a cut-off value of 0.80, had an overall sensitivity of 100% (95% CI, 95-100) and a spe cificity of 98.8% (95% CI, 92.0-99.6). An acute thrombosis process did not influence the performance of the test. We conclude that this test is easy and rapid to perform in every day practice and fulfills the c riteria for a screening test. Blood Coag Fibrinol 9:355-359 (C) 1998 L ippincott-Raven Publishers.