Direct thrombin inhibitors and factor xa inhibitors can influence the diluted prothrombin time used as the initial screen for lupus anticoagulant

CONTEXT: Lupus anticoagulant (LA) is a heterogeneous group of antiphospholipid antibodies. Among others, diluted prothrombin time (dPT) is a sensitive screening test for LA; however, the interpretation of LA tests is difficult in patients treated with anticoagulants. The effect of different types of anticoagulants on the result of LA tests, particularly on dPT, has not been studied extensively. OBJECTIVE: To determine whether the direct thrombin inhibitors lepirudin and argatroban and the predominantly factor Xa inhibitors enoxaparin, danaparoid, and fondaparinux could interfere with LA screening based on dPT. DESIGN: Each drug was added to normal and LA-positive plasmas in clinically relevant concentrations. Each sample was tested for dPT. Samples with factor Xa inhibitors were investigated before and after addition of heparinase. Mixing and confirmatory tests for LA were not performed. RESULTS: In the presence of lepirudin or argatroban, dPT increased notably and the dPT ratio exceeded the cutoff value even at subtherapeutic concentrations resulting in false positivity. With increasing factor Xa inhibitor concentrations, a linear increase of dPT ratios and false-positive results were also demonstrated. Although heparinase could almost completely neutralize the anti-Xa effect of all investigated factor Xa inhibitors, dPT ratio returned to the basal level only in case of enoxaparin. CONCLUSIONS: Here we provide evidence that both the direct thrombin and indirect factor Xa inhibitors influence dPT assay for LA, causing false positivity. This should be considered when interpreting LA results during anticoagulant therapy. However, dPT seems to be a reliable test for LA screening under enoxaparin therapy after neutralization by heparinase.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Peer-reviewed pharmacology and drug-development research relevant to antithrombotic agents and leech-derived compounds. Indexed in PubMed and verified against the NCBI record.

Leech-derived molecules this paper discusses, each with a full profile in the ASH compound registry:

Explore cómo esta investigación se conecta con la práctica clínica

More peer-reviewed studies in Desarrollo de fármacos.

• Novel Leech Antimicrobial Peptides — Hirunipins — Kumar et al. (2025)
• Medicinal Leech Genome Assembly — Anticoagulant Gene Catalog — Kvist et al. (2020)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• HIRUDOTHERAPY IN PRESBYACUZIS PRAECOX IN CLEAN-UP WORKERS AFTER THE CHORNOBYL ACCIDENT DURING THE POST-CATASTROPHE YEARS — Zabolotnyi D, Mishchanchuk N (2019)
• [Hirudo medicinalis-leech applications in plastic and reconstructive microsurgery--a literature review] — Knobloch K et al. (2007)
• Recombinant hirudin in clinical practice: focus on lepirudin — Greinacher A, Lubenow N (2001)
• In-vitro antileishmanial potential of peptide drug hirudin — Khan H et al. (2017)
• Parenteral anticoagulants: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines — Garcia DA, Baglin TP, Weitz JI, Samama MM (2012)
• Direct thrombin inhibitors — Lee CJ, Ansell JE (2011)
• Updates on Use and Monitoring of Direct Thrombin Inhibitors — Navaei A et al. (2026)

Browse all ASH-analysed research →