In reviewing an article by Dave McGlasson, Wilford Hall USAF Medical Center, San Antonio, that compares several dilute Russell viper venom (DRVVT) kits for their accuracy in detecting lupus anticoagulant, I noticed that Dave advocates for DRVVT ratio normalization, using the attached formula. I may be behind the times, but this is a new concept to […]

From “Sunny,” What is the reason for not using prothrombin time (PT) in investigating lupus anticoagulant (LA)? It is also a phospholipid-dependent assay. Thanks. Hello, and thank you for your question. Although a particularly avid LA may on occasion prolong the PT, PT reagent (thromboplastin) phospholipid is typically concentrated enough to neutralize plasma LA so […]