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BCH Order Code LAB4028 Verify Now Assay for Aspirin Effect

Important Note

The following medications may cause changes in platelet reactivity. Patients receiving these medications should not be tested until after the time listed in parentheses beside the medication:

  1. Antiplatelet Agents:
    1. Plavix (5 days)
    2. Ticlid  (5 days)
    3. Aggrenox (10 days)
    4. Persantine (12 hours)
    5. Pletal/Cilostazol (12 hours)
  2. NSAID
    1. ibuprofin (Motrin, Advil) (8 hours)
    2. Naproxen (Aleve, Anaprox, Naprelan, Naprosyn) (24 hours)
    3. Diclofenac (Voltaren, Cataflam) (24 hours)
    4. Indocin (24 hours)
    5. Feldene (50 hours)
  3. GP IIb/IIIa Inhibitors
    1. Aggrastat (tirofiban) (2 days)
    2. Integrilin (epitifibatide) (2 days)
    3. ReoPro (abciximab) (2 weeks)

Useful For

The VerifyNow System detects plateley activity by measuring in vitro platelety aggregation in a blood sample exposed to specific agonists.  This includes inhibition of platelet activity in response to antiplatelet therapies.  The VerifyNow Aspirin Test is a qualitative test to aid in the detection of platelet function due to aspirin ingestion.

Performing Laboratory

Boulder Community Health

Specimen Requirements

NOTE:  Specimens must be walked to the Laboratory.  Any specimens sent through the pneumatic tube system will be rejected.

Follow one of the following procedures:

Direct Venipuncture 

Specimen Type: Whole blood 
Container/Tube: 2 Greiner Bio-One partial-fill vacuette tubes with 3.2% sodium citrate (blue top). Greiner #454322 + clearing tube 
Volume: 2.0 mL each 

Collection Instructions: 

  • Collect all tubes of whole blood using a 21 gauge or larger needle. 
    • Butterfly (21 gauge) is OK to use.  
  • First collect a clearing tube (at least 2 mL) making sure the clearing tube does not contain any platelet inhibiting substances (e.g. EDTA). 
  • Clearing tube does not need to be sent to lab 
  • Fill the second and third tube (sample tubes) to the black line (1/2 tube). 
  • Do not under fill. 
  • If drawing blood for a CBC at the same time, fill the CBC tube last. 
  • Gently invert the Greiner tubes at least 5 times to ensure complete mixing of the contents. 
  • Samples with evidence of clotting should not be used. 
  • Do not shake, as that may give incorrect results. 
  • Label the tubes with the patient ID, date and time it was drawn. 
  • Do not refrigerate. 
  • Send both Greiner tubes to the Laboratory

 

Indwelling Catheter 

Specimen Type: Whole blood 
Container/Tube: 2 Greiner Bio-One partial-fill vacuette tube with 3.2% sodium citrate (blue top). Greiner #454322 
Volume: 2.0 mL 
Collection Instructions: 

  • Discard the first 5 mL from an indwelling catheter to clear the line. 
  • Ensure the catheter is free of clots. 
  • Immediately transfer blood to a 2 mL Greiner Bio-One partial fill vacuette tube with 3.2% sodium citrate (blue top). Greiner #454322. 
  • Fill both tubes to the black line (1/2 tube). 
  • Do not under fill. 
  • If drawing blood for a CBC at the same time, fill the CBC tube last. 
  • Gently invert the Greiner tubes at least 5 times to ensure complete mixing of the contents. 
  • Samples with evidence of clotting should not be used. 
  • Do not shake as that may give incorrect results. 
  • Label the tubes with the patient ID, date and time it was drawn. 
  • Do not refrigerate. 
  • Send both Greiner tubes to the Laboratory

 

Specimen Rejection:

  • Samples sent through the pneumatic tube system
  • Clotted Specimens
  • Under/over-filled specimens
  • Specimens greater than 4 hours old

Specimen Transport Temperature

Specimen Stability:
Ambient: 4 hours 
Refrigerate: not acceptable 
Frozen: not acceptable 
Laboratory Retention: 24 hours 
 

Methodology

Turbidimetric-based optical detection to measure platelet-induced aggregation.

Reference Values

Interpretive Comment:

 

Verify Now Aspirin assay results are reported in Aspirin Reactivity Units (ARU)

ARU values below 550 are indicative of effective aspirin inhibition of platelet activity.

ARU values of 550 or above are indicative of ineffective aspirin inhibition of platelent activity.

Day(s) Test Set Up

Monday through Sunday

 

Usual turn-around-time 1 day

Test Classification and CPT Coding

85576

LOINC Code Information

49011-0