Laboratory Testing for Lupus Anticoagulants: Diagnostic Criteria and Use of Screening, Mixing, and Confirmatory Studies

The presence of lupus anticoagulants (LA) in plasma is a strong risk factor for thromboembolism and fetal loss. Because of this, demand for testing for LA is increasing, but the performance of clinical laboratories in terms of its detection is still a matter of concern. This is due in part to the lack of specific tests but also to the lack of standardization and application of the diagnostic criteria. The aim of this article is to review the diagnostic criteria and the many issues that may affect test results.