Platelet Function P2Y12 (Verify Now)


Sunquest Code:P2Y12  
Epic Code:LAB5338Epic Name:Platelet Function P2Y12
Synonyms:Platelet Function by VerifyNow; Platelet Function P2Y12; P2Y12 Assay; Clopidogrel; Plavix
Methodology:Turbidmetric-based optical detection; VerifyNow
Turnaround Time:Performed and reported 24 hours/day.
Special Instructions:
This test requires a special tube be used that can only be filled to one amount for proper testing results. Test must be performed within 4 hours of collection. Specimen must be hand delivered; do not send via Pneumatic Tube System (PTS). This test is intended for patients on anti-platelet medication and is not intended for patients with genetic abnormalities.

Patients who have been treated with glycoprotein IIb/IIIa inhibitors should not be tested until the platelet function has recovered. This time period is approximately 48 hours after discontinuation of eptifibatide and tirofiban, and 14 days after discontinuation of abciximab. Other platelet drugs such as P2Y12 inhibitors (e.g. clopidogrel), NSAIDs, etc. may also affect the results of this assay.


Collection Instructions

Specimen:Blood
Optimal Volume:Two 2 mL Greiner tubes
Minimum\Peds Volume:One 2 mL Greiner tube
Container:9 NC Coagulation Sodium Citrate (Greiner tube)
Collection Instructions:
  • Peripheral Samples: Blood samples should be obtained from an extremity free of peripheral venous infusions. Whole blood samples must be collected using a 21 or larger gauge needle. Collect a discard sample of at least 2 mL in a tube containing sodium citrate or no additive.  Gently invert the sample tubes at least 5 times to ensure complete mixing of the contents.
  • Indwelling Venous Catheters: Collect a discard sample of at least 5 mL in a tube containing sodium citrate or no additive. Transfer blood to the blood collection tubes immediately after collection. Gently invert the sample tubes at least 5 times to ensure complete mixing of the contents.


Only one test may be assayed per tube. If ordering both ASA and P2Y12, additional specimens are required.
NOTE: If drawing an EDTA tube at the same time as sample collection for VerifyNow Aspirin test, fill the EDTA tube last.
Causes for Rejection:Specimen that is clotted, hemolyzed, underfilled, overfilled, centrifuged, not tested within 4 hours of collection, sent via PTS, or stored in the refrigerator or freezer prior to testing.


Processing and Shipping

Specimen Processing:Whole blood. Do not process.
Shipping Instructions:Hand-deliver. Must arrive for testing within 4 hours of collection at room temperature.
Test Performed at or Referral Lab Coagulation  (UMMC-East Bank, Southdale)


Interpretive

Reference Range:
Normal individuals not taking P2Y12 180-376 PRU
Evidence of P2Y12 receptor blockade Less than 180 PRU
Appropriate response to anti-platelet therapy for cardiology patients Less than 208 PRU
Optimal therapeutic and pre-surgical target Not established

Test results are reported in P2Y12 Reaction Units (PRU) which indicate the amount of ADP-mediated aggregation specific to the platelet P2Y12 receptor and is used to measure the effects of anti-platelet drugs specific to this receptor, such as clopidogrel. The reference range for individuals NOT receiving a P2Y12 inhibitor is 180-376 PRU. PRU levels less than 180 are specific evidence of an anti-platelet effect due to P2Y12 receptor blockade. Literature suggests that a PRU value less than 208 is an appropriate response to anti-platelet therapy for cardiology patients (Reference: MJ Price et al Circulation 2011:154:1132-1137). Optimal therapeutic and pre-surgical PRU targets have not been established.

Assay performance is affected by hematocrit values less than 33% or greater than 52%, and platelet counts less than 119 x 109/L or greater than 502 x 109/L.
Use:Measures the degree of platelet function in patients who are taking the thienopyridine class of drugs including clopidogrel and prasugrel.


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