This private pharmacogenetic blood test analyses CYP2C19 gene variants to check whether your liver can convert clopidogrel into its active antiplatelet form. The catalogue test price is £312.50 plus a £50 phlebotomy fee, and results are available in 10 days.
NICE guidance recommends CYP2C19 genotype testing after ischaemic stroke or transient ischaemic attack (TIA), and before or during antiplatelet therapy after coronary stenting.
Written by Mr Stephen Lingam. Reviewed by Prof Darrel Francis (GMC 4062833) on 18/10/2026.
Clopidogrel must be activated by the CYP2C19 enzyme in the liver. Genetic variants in CYP2C19 reduce this activation, leaving platelets less protected against clotting.
Never stop or change antiplatelet medication without speaking to your prescribing cardiologist, neurologist or GP. The DNA test works regardless of current medication.
No fasting or special preparation is required. A single venous blood draw at 117a Harley Street is all that is needed.
Yes. CYP2C19 also metabolises several proton pump inhibitors (such as omeprazole) and certain antidepressants, so the genotype remains a permanent part of your medical record.