Use of the dilute Russell viper venom time (dRVVT): its importance and pitfalls.

Antiphospholipid antibodies (APA) are now recognized as the most common cause of acquired thrombophilia. These antibodies may lead to thrombosis in both arterial and venous sites. Lupus anticoagulants (LA) are the most significant risk factor among the various APAs. The detection of LAs remains challenging to most laboratories. Multiple screening tests are recommended (e.g. APTT, dilute PT and dRVVT). The dRVVT is one of the most important screening procedures. In many instances, commercially available dRVVT systems include a screening reagent with low PL concentration and a confirmatory product with high PL concentration. There are a number of commercially available dRVVT test systems. These reagents vary in phospholipid origin and concentration as well as source of Russell viper venom (RVV). It is imperative for laboratories to be well informed regarding reagent composition and laboratory performance.