Pretest direct oral anticoagulant removal is highly effective in lupus anticoagulant testing while on direct oral...

Direct oral anticoagulants (DOACs) may cause false-positive lupus anticoagulant (LA) results by interfering with phospholipid-dependent coagulation assays. Current guidelines discourage LA testing during DOAC therapy unless anticoagulant interference is removed.

To evaluate the real-life efficacy of routine pretest DOAC removal in LA testing.

Consecutive DOAC-treated patients screened for LA at a tertiary center between August 2020 and December 2024 were analyzed. Blood samples were collected between 1 and 24 hours after the last DOAC dose. LA testing was performed after the DOAC-Stop (Haematex Research) treatment. Positive LA results were repeated within 1 month (≥24 hours after the last DOAC dose), and if still positive, after ≥3 months. Antiphospholipid antibodies were determined by enzyme-linked immunosorbent assay.

Among 701 patients (51.4% women; median age 49 years [40.0-60.0]), mostly with venous thromboembolism (n = 548, 78.2%), 56 (8.0%) had positive LA screening and 31 (4.4%) had positive confirmatory tests after DOAC removal. Baseline characteristics were comparable, except for a higher proportion of women among screening-positive patients. Within 1 month, 26 of 31 patients available for retesting remained LA-positive. Persistent antiphospholipid antibody positivity after ≥12 weeks was confirmed in all 26 patients, including 19 with triple-positive antiphospholipid syndrome (APS), 4 double-positive APS, and 3 single-positive APS (isolated LA).

Pretest DOAC removal followed by 3-step LA testing using dilute Russell's viper venom time and activated partial thromboplastin time-based assays enabled reliable LA assessment in routine practice, with positive results observed exclusively in patients fulfilling APS criteria.