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Test Code LAB90132 (COX-1) Aspirin Platelet Inhibition Test

Important Note

This test can only be drawn and performed at the Riverside Hospital

Reporting Title

(Cox-1) Platelet Inhibition Test

Methodology

Measures the platelet response to aspirin by arachidonic acid initiated reaction

Performing Laboratory

OhioHealth Laboratory Services-RMH Core Laboratory

Specimen Requirements

Involves special collection requirements.  Kits for drawing this test have been supplied to units that will be ordering the test.  The kits include 2.0 mL Greiner Bio-One partial fill vacuette tubes with 3.2% sodium citrate (blue-top), a discard tube, a 21 gauge needle and instructions for collection. 

 

Draw 1 Greiner blue-top tube using a 21 gauge needle to the black line on the tube (1/2 tube).  Do not under fill. 

Invert gently 5 times to mix blood.

Specimens cannot be sent through the pneumatic tube system.  Please call 566-5684 to have a phlebotomist pick up the sample.

Testing must be completed within 4 hours of collection.

 

NOTES:  Limitations of the test include interference by other antiplatelet drugs such as Glycoprotein IIb/IIIa inhibitors.   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 administration for abciximab (ReoPro) and up to 48 hours for eptifibatide (Integrilin) and tirofiban (Aggrastate).  The platelet function recovery time varies among individuals and is longer for patients with renal dysfunction.  NSAIDs (e.g. ibuprofen) or anti-platelet drugs like Aggrenox (aspirin/extended-release dipyridamole), Persnatine (dipyridamole), and Pletal (citostazol), can also interfere with test results.  the effect of hematocrits less than 29%, hematocrits greater than 56%, platelet counts less than 92,000 per microliter, fibrinogen less than 164 mg/dL and fibrinogen greater than 529 mg/dL have not been tested. 

 

 

 

Specimen Transport Temperature

Ambient

Reference Values

The level of platelet dysfunction due to aspirin is measured in Aspirin Reaction Units (ARU) with a low ARU reflecting platelet dysfunction due to aspirin.  An ARU less than 550 suggest platelet dysfunction due to aspirin.  The VerifyNow Aspirin Test results should be interpreted in conjunction wtih other available clinical and laboratory data. 

Day(s) Test Set Up

Monday through Sunday

CPT

85576