Specimen Requirements

Involves special collection requirements. Kits for drawing this test have been supplied to the 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 tube), a discard tube and instructions for collection.  

Collection Instructions:

• Draw 2 Greiner blue-top tubes using a 21-gauge needle to the black line on the tubes (1/2 tube). Do not underfill.  
• Invert gently 5 times to mix blood. 
• Specimens cannot be sent through the pneumatic tube system. They must be hand delivered to the lab.  
• Testing must be completed within 4 hours of collection.  

Note: 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 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 (Aggrastat). The platelet function recovery time varies among individuals and is longer for patients with renal dysfunction. Cilostazol may affect test results; the average duration of the platelet inhibitory effect is 12 hours. Patients with inherited platelet disorders such as von Willebrand Factor Deficiency, Glanzmann Thrombasthenia and Bernard-Soulier syndrome have not been studied with the VerifyNow PRUTest. The VerifyNow PRUtest is not intended for use with these types of platelet disorders. Aspirin and NSAIDs show no significant inhibition of the PRU value. The effect of platelet counts less than 119,000 X 109 /L, platelet counts greater than 502,000 X 109 /L, hematocrits less than 33%, and hematocrits greater than 52% have not been studied.