Antiphospholipid Antibody Testing in Male Patients
Yes, antiphospholipid antibody testing should be performed in male patients when clinically indicated, as antiphospholipid syndrome affects both males and females, particularly in cases of unexplained thrombosis or stroke. 1
When to Test Male Patients for Antiphospholipid Antibodies
Testing is recommended in the following clinical scenarios:
High Priority Indications:
- Unprovoked venous thromboembolism (VTE)
- Arterial thrombosis in young patients (<50 years)
- Thrombosis at unusual sites
- Cryptogenic stroke, especially in younger patients
- History of thrombosis with concurrent autoimmune disease 1, 2
Moderate Priority Indications:
- Provoked VTE in young patients
- Recurrent thrombotic events 2
Low Priority Indications:
- VTE/arterial thrombosis in elderly patients with multiple vascular risk factors 2
Recommended Testing Panel
The International Society on Thrombosis and Haemostasis (ISTH) recommends comprehensive testing that includes:
- Lupus anticoagulant (LA) - detected according to ISTH guidelines using a 3-step methodology (screening, mixing, and confirmation)
- Anticardiolipin antibodies (aCL) - IgG and IgM isotypes
- Anti-β2 glycoprotein I antibodies (aβ2GPI) - IgG and IgM isotypes 1
All three tests should be performed concurrently, as triple positivity (positive for all three tests) carries the highest thrombotic risk 1, 2.
Testing Considerations and Potential Pitfalls
Timing of Testing:
- Blood samples should ideally be collected before starting anticoagulant therapy 2
- If the patient is already on anticoagulation:
- For LA testing during direct oral anticoagulant (DOAC) therapy, pretest DOAC removal procedures should be used
- Testing during vitamin K antagonist therapy should be interpreted with caution
- Taipan snake venom time/Ecarin time (TSVT/ET) can be used in patients on anti-Xa DOAC or vitamin K antagonist therapy 1
Confirmation of Positivity:
- Repeat testing is essential at least 12 weeks after the initial positive result to confirm persistence of antibodies 1
- Transient positivity is not sufficient for antiphospholipid syndrome diagnosis 1
Interpretation of Results:
- Results should be interpreted according to local cutoff values (typically >99th percentile of normal controls) 1
- Triple positivity (LA, aCL, and aβ2GPI) or double positivity (aCL and aβ2GPI with concordant isotype) increases confidence in diagnosis 1
- IgG isotype is generally considered more clinically relevant than IgM 1
- Isolated IgM positivity, particularly aCL IgM, is associated with lower thrombotic risk 2
Clinical Management Based on Testing
In male patients with positive antiphospholipid antibodies:
For patients with isolated antiphospholipid antibody but not fulfilling criteria for antiphospholipid syndrome: Antiplatelet therapy alone is recommended to reduce recurrent stroke risk 1
For patients meeting criteria for antiphospholipid syndrome: Anticoagulation with warfarin is reasonable to reduce recurrent stroke/TIA risk 1
For patients with antiphospholipid syndrome, history of thrombosis, and triple-positive antibodies: Warfarin is preferred over rivaroxaban, which is associated with excess thrombotic events 1
For patients with confirmed antiphospholipid syndrome treated with warfarin: Target INR between 2 and 3 is reasonable to balance bleeding risk against thrombosis risk 1
Conclusion
Antiphospholipid antibody testing is indicated in male patients with unexplained thrombotic events, particularly younger patients with arterial thrombosis, stroke, or unusual site thrombosis. A comprehensive panel including LA, aCL, and aβ2GPI should be performed, with repeat testing after at least 12 weeks to confirm persistence of antibodies.