Interpreting VerifyNow® P2Y12 Test Results
The VerifyNow P2Y12 Test is a whole blood test to measure the level of platelet P2Y12 receptor blockade. Some antiplatelet medications [e.g. Plavix® (clopidogrel) and Effient® (prasugrel)] are designed to specifically block the P2Y12 receptor to reduce the risk of ischemic events.
What is Reported?
The lab report will look similar to the following:
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Patient Example
P2Y12 Results Patient A Units Reference Range
P2Y12 Reaction Units 132 PRU See Below (1)
BASE Platelet Reactivity 317 Base PRU 194-418 (2)
% P2Y12 Inhibition 58 % See Below (1,3)
(1) PRU reference range is 194-418. Post Drug Results: Lower PRU levels and/or
higher % inhibition are associated with expected antiplatelet effect. Values
may be below the stated reference range above. The post-drug PRU values reported
in the VerifyNow P2Y12 Test package insert are 18-435.
(2) Base PRU Range: Range does not change pre or post-drug as it is not affected
by the presence of a P2Y12 inhibitor and represents pre-drug PRU value. Base
result less than 194 may be indicative of platelet dysfunction due to conditions outside
of P2Y12 inhibitors pathway (e.g.,IIb/IIIa inhibitors).
(3) Presurgical Application: Return to baseline discontinuation of P2Y12 inhibitors.
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P2Y12 Reaction Units (PRU) indicate the amount of ADP-mediated aggregation specific to the platelet P2Y12 receptor.
BASE (Base PRU) – indicates the amount of mediated aggregation specific to the platelet PAR-1 and PAR-4 receptors.
The BASE result is normalized to report units that are equivalent to baseline (pre-drug) PRU values.
Percent (%) P2Y12 Inhibition – is the percent change from baseline aggregation, and is calculated from the PRU result and the BASE result.
Interventional Procedure Application
Up to 1/3 of patients on antiplatelet medications may not receive the expected platelet inhibiting effect.5
Numerous factors may cause inadequate platelet response to antiplatelet therapies,6 including:
• Drug Interactions (e.g. Proton Pump Inhibitors)
• Genetic differences
• Pre-existing health conditions (e.g. diabetes)
• Non-compliance
Pre-Surgical Application
- Patients who have been administered P2Y12 inhibitors such as clopidogrel and prasugrel are at risk of perioperative bleeding.
- It is recommended to discontinue P2Y12 inhibitors for 5-7 days prior to surgery7, as it may take several days for platelet function to be restored.8
- Studies show that there is patient variability in response to P2Y12 inhibitors5, and some patients may not need to wait 5-7 days8 to return to baseline platelet function.
After discontinuation, high P2Y12 % inhibition values indicate a residual antiplatelet effect.
Low P2Y12 % inhibition values are reported if the P2Y12 inhibitor is no longer producing the expected antiplatelet effect.
Conditions that May Affect Test Results:
• Patient’s exposure to GP IIb/IIIa inhibitors within:
- 48 hours of eptifibatide (Integrilin®)
- 10 days of abciximab (ReoPro®)
• Improper sample collection (platelet activation)
The VerifyNow P2Y12 Test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician. Please refer to Effient® Prescribing Information. Daiichi Sankyo, Inc and Eli Lilly and Company. Please refer to Plavix Prescribing Information. Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership.