A simplified algorithm for the laboratory detection of lupus anticoagulants: utilization of two automated integrated tests.

Diagnosis of antiphospholipid antibody syndrome includes laboratory testing for lupus anticoagulants (LAs). Guidelines for testing have been published, but approaches vary, often incorporating multiple tests. We evaluated the performance of the activated partial thromboplastin time using 2 reagents, a dilute Russell viper venom time, and a hexagonal phospholipid assay for detecting LAs in 105 adults. Of the patients, 26 were taking anticoagulants at the time of testing. Based on findings, an algorithm was derived for optimal detection of LAs using 2 easily performed, automated, integrated test systems. Of 105 patient samples, 30 (28.6%) were positive for LAs, using the algorithm interpretive criteria. Of these 30 positive results, 10 were detected in the 26 patients taking anticoagulants. Analysis by chi2 showed no difference in performance of the integrated tests between samples from patients taking and not taking anticoagulants. The algorithm is offered as a means for standardization of laboratory testing for LAs.