Protein S exhibits anticoagulant activity independent of activated protein C (APC). An automated factor Xa-based one-stage clotting assay was developed that enables quantification of the APC-independent activity of protein S in plasma from the ratio of clotting times (protein S ratio [pSR]) determined in the absence and presence of neutralizing antibodies against protein S. The pSR was 1.62 +/-...

BACKGROUND/AIM Thrombophilia is a multifactorial predisposition for thromboembolism affecting about a tenth of any population. We investigated whether genetic counseling combined with molecular testing for two common dominant mutations (coagulation factor V Leiden and prothrombin G20210A) may increase prevention of venous thromboembolic incidents in individuals with a positive family history co...

Because of the potential implications of results of genetic analyses of thrombophilic mutations, laboratories must undertake stringent internal quality control measures and participate in external quality assurance (QA) programs. A small number of external QA surveys of thrombophilic defects have been conducted across a large number of molecular laboratories and generally have indicated favorab...

Abnormally short activated partial thromboplastin times (APTTs) are associated with an increased risk of thrombotic disorders. We have examined the status of coagulation activity in subjects with short APTTs. In addition, the presence of the thrombotic risk factors G1691A-factor V, G20210A-prothrombin gene mutation and factor VIII coagulant activity (FVIII:C) was determined. Plasma levels of TA...