Updates in Antiphospholipid Syndrome Laboratory Diagnosis.

Dramatic improvements have been made in antiphospholipid syndrome (APS) diagnosis, but work is still needed around standardization of laboratory practice and lupus anticoagulant (LA) testing with anticoagulated samples. LA testing in anticoagulated patients is common, and can lead to false positivity and possibly false negativity. For patients whose anticoagulation cannot be held, LA testing accuracy can be improved by activated carbon pre-treatment or alternative LA reagents. Solid phase testing for antiphospholipid antibodies remains incompletely harmonized and recent International Society on Thrombosis and Haemostasis (ISTH) and American College of Rheumatology (ACR)/ European League against Rheumatism (EULAR) guidelines do not completely agree.