Interpreting VerifyNow Aspirin Test Results
The VerifyNow® Aspirin Test is a whole blood test to aid in the detection of platelet inhibition due to aspirin therapy.
What is Reported?
The lab report will look similar to the following:
*************************************************************************************************
Result Name Result Units Reference
Platelet Function ASPIRIN 400 ARU See Below (1)
(1) Test results are reported in Aspirin Reaction Units (ARU).
350-549 ARU – therapeutic range for platelet function.
550-700 ARU – NON-therapeutic range for platelet function.
**************************************************************************************************
Aspirin Reaction Units (ARU) indicate the amount of thromboxane A2-mediated activation of GP IIb/IIIa receptors involved in platelet aggregation. ARU is calculated as a function of the rate and extent of platelet aggregation. Expected values are in the range of 350-700 ARU.
Pre-Surgical Screen
Prior to surgery, the VerifyNow Aspirin Test can aid in guiding clinical decisions whether to discontinue aspirin therapy (when at increased risk of perioperative bleeding from Plavix®/clopidogrel or Effient®/Prasugrel) or to remain on aspirin to improve graft patency.1 Medical research suggests that there is patient variability in response to aspirin.2 Values less than 550 ARU are reported if aspirin is producing the expected antiplatelet effect. After discontinuation, ARUs less than 550 indicate residual inhibition due to aspirin.
Therapeutic Response
Medical research suggests there is patient variability in response to aspirin.2 ARU values less than 550 are consistent with aspirin-induced inhibition of platelet function. Refer to the chart.
Interfering Substances3
• Antiplatelet agents
• NSAIDs
• GP IIb/IIIa inhibitors – e.g. ReoPro® and Integrilin®
The VerifyNow Aspirin Test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician.
Download VerifyNow Aspirin Interpreting Results Card