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Test Code Aspirin Platelet Function Aspirin Platelet Function

Important Note

  • Must be drawn at Outpatient Lab at the Main Campus
  • Must be walked down to the Laboratory

Additional Codes

Aspirin Platelet Function

Aspirin

Causes for Rejection

  • Underfilled
  • Overfilled
  • Sent through pneumatic tube system

Test Details

Aspirin VerifyNow Platelet Reactivity (ARU): Test results are in Aspirin Reactivity Units (ARU). This measures the etent of platelet dysfunction due to aspirin ingestion.

If >550 ARU - Platelet dysfunction consistent with aspirin not detected.

If < 550 ARU - Platelet dysfunction consistent with aspirin detected. 

Administration of a P2Y12 inhibitor such as clopidogrel, prasugrel or ticagrelor may cause a reduction in the ARU with the VerifyNow Aspirin Reactivity test. However, this effect is generally not great enough to cause miscategorization of patients as to whether or not they have platelet dysfunction due to aspirin. Patients who have been treated with Glycoprotein IIb/IIIa inhibitor drugs should not be tested until platelet function has recovered. This time period is approximately 14 days after discontinuation of drug adminstration for abciximab (ReoPro) and up to 48 hours for eptifibatide (Integrilin) and tirofiban (Aggrastat). Results should be interpreted in conjunction with other clinical and laboratory data available to the clinician.

Collection

  1. Using a 21 gauge needle or larger (butterfly is acceptable), collect tubes in the following order:
    1. One (1) clear top Vacutainer tube - partial fill 3 mL draw
    2. Two (2) blue Greiner tubes - These are partial fill 2 mL draw tubes. Fill exactly to the black arrow on the tube; do not over or under fill.
  2. Immediatly following collection, thoroughly mix each sample by gently inverting each tube 5 times to prevent clotting
  3. Additional tubes may be collected after these tubes have been collected
  4. Specimen MUST be walked down to the Laboratory.

Test Limitations

 

The Aspirin VerifyNow test performance has been validated for hematocrit values between 29-56% and platelet counts > 92 K/uL. Results outside of these parameters have not been studied and results may be affected.