Understanding Lab Tests for Aspirin Resistance
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Aspirin resistance is a condition where the body does not respond adequately to aspirin's blood-thinning (antiplatelet) effects, potentially reducing its protective benefits for cardiovascular health. This condition cannot be diagnosed through physical examination alone and requires specialized laboratory testing to detect.
Recommended Test
AspirinWorks® 11-Dehydrothromboxane B2 (11-dhTXB2) with Creatinine
This specialized test measures 11-dhTXB2, a metabolite that reflects platelet activity and thromboxane production. Elevated levels indicate that platelets are still aggregating despite aspirin therapy, suggesting aspirin resistance. The test includes creatinine measurement to ensure accurate interpretation of results based on kidney function.
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Why Testing for Aspirin Resistance is Important
Many people take low-dose aspirin to prevent heart attacks and strokes by reducing blood clot formation. However, some individuals may have aspirin resistance, meaning their platelets continue to aggregate normally despite aspirin therapy. Laboratory testing is fundamental for determining whether aspirin is providing the intended antiplatelet protection.
How Aspirin Resistance is Detected
Aspirin resistance is diagnosed by measuring specific biomarkers in the blood that indicate platelet activity. When aspirin is working effectively, it blocks the production of certain substances that promote blood clotting. If these substances remain elevated despite aspirin therapy, it suggests resistance to the medication.
Who Should Consider Testing
Testing for aspirin resistance may be considered for individuals who are taking aspirin for cardiovascular protection but have experienced cardiovascular events, or for those whose healthcare provider wants to verify that aspirin therapy is providing optimal antiplatelet effects. This testing can help guide treatment decisions and medication adjustments.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis, treatment decisions, and medication management.
