VerifyNow for Clopidogrel:
- Values less than 194 PRU are specific evidence of a P2Y12 inhibitor effect
VerifyNow for Aspirin:
- ≤ 549: Evidence of platelet dysfunction due to aspirin
- > 550: No evidence of aspirin-induced platelet dysfunction
ASA-specific VerifyNow uses arachidonic acid as an agonist for platelet aggregation onto fibrinogen-coated beads.
VerifyNow (P2Y12) uses adenosine diphosphate and is more commonly utilized to detect platelet dysfunction due to clopidogrel.
Degree of platelet aggregation is recorded as aspirin reaction units (ARUs) or P2Y12 reaction units (PRUs).
Abnormally functiong platelets are defined as ARU <550 or PRU 208 (U of Cincinnati lab normal value, cutoff not universally defined).
Martin, G., Shah, D., Elson, N., Boudreau, R., Hanseman, D., Pritts, T., Makley, A., Foreman, B. and Goodman, M. (2018). Relationship of Coagulopathy and Platelet Dysfunction to Transfusion Needs After Traumatic Brain Injury. Neurocritical Care.