Summary
Laboratory tests for lupus anticoagulants (LA) are commonly performed to evaluate
thrombosis or suspected phospholipid antibody syndromes. To determine current LA testing
practices, and if they conform to published recommendations, two questionnaires were
distributed to clinical laboratory members of the North American Specialized Coagulation
Laboratory Association (NASCOLA) and the ECAT Foundation (ECAT). The first and second
questionnaires were completed by 113 and 96 laboratories, respectively. Commonly performed
LA tests included the dilute Russell’s viper venom time, LA sensitive activated partial
thromboplastin time and hexagonal phospholipid test. Although some laboratories did
single LA tests if requested, the majority complied with published recommendations:
to use platelet poor plasma for LA tests; to use two or more screening tests, representing
different assay principles, and one assay having a low phospholipid concentration
to exclude LA; to confirm LA phospholipid dependency by the method giving an abnormal
LA screen; to document the inhibitor activity on pooled normal plasma; and not to
use phospholipid antibodies to confirm LA. A minority (<35%) followed the recommendations
to exclude factor deficiencies and factor inhibitors as the cause of an abnormal LA
test. After participating, 32% of laboratories had changed practices and 20% indicated
that they would be changing practices. While most laboratories generally follow published
guidelines for LA testing, few follow recommendations to evaluate for other coagulation
abnormalities. Questionnaires may be helpful quality initiatives to improve compliance
with laboratory testing guidelines and recommendations.
Keywords
Lupus anticoagulant - phospholipid antibodies - coagulation inhibitors - ISTH guidelines
