Pretest DOAC removal is highly effective in lupus anticoagulant testing while on direct oral anticoagulants: a real-life experience.

Background

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.

Aim

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

Methods

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

Results

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%) positive confirmatory tests after DOAC removal. Baseline characteristics were comparable, except for a higher proportion of women among screening-positive patients. Within one month, 26 of 31 patients available for retesting remained LA-positive. Persistent aPL positivity after ≥12 weeks was confirmed in all 26 patients, including 19 with triple-positive antiphospholipid syndrome (APS), four double-positive APS and three single-positive APS (isolated LA).

Conclusions

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