The VerifyNow® Aspirin Assay is a whole blood assay to aid in the detection of platelet inhibition due to aspirin therapy.

What is Reported?

The lab report will look similar to the following:

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Result NameResultUnitsReference
Platelet Function ASPIRIN400ARUSee 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.
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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 Aspirin assay can aid in guiding clinical decisions whether to discontinue aspirin therapy (when at increased risk of perioperative bleeding from Plavix®/clopidogrel ) 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®

References

  1. Eagle, et. al. ACC/AHA 2004. Guideline Update for Coronary Artery Bypass Graft Surgery.
  2. Gum, et. al. Pro_le and Prevalence of Aspirin Resistance in Patients with Cardiovascular Disease. J Am Coll Cardiol 2001;88:230-235.
  3. Refer to the VerifyNow Aspirin Assay package insert for complete details.

The VerifyNow Aspirin Assay test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician. VerifyNow is a registered trademark of Accumetrics, Inc.. Integrilin is a registered trademark of Milennium Pharmaceuticals. ReoPro is a registered trademark of Centocor, Inc.. Plavix is a registered trademark of Sanofi-Synthelabo, Inc..