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Platelet Aggregation

This assay must be scheduled in advance. Call 714-456-5030 to make an appointment. 


Patient must come to the UC Irvine Outpatient Drawing Area in Pavilion III. The specimen must be drawn Monday through Friday between 9 a.m. and 2 p.m. If special circumstances preclude the patient from traveling to the medical center, have the scheduler call during business hours to discuss alternatives with the director or specialist 714-456-5030.

Inpatients at UC Irvine Medical CenterCall 714-456-5030 to schedule an appointment.

Inpatients (non-UC Irvine facilities)

Inpatients in referring facilities cannot travel to UC Irvine for specimen collection; therefore, strict guidelines must be followed in order to obtain an acceptable specimen.

  • Patient and control should be drawn into 3.2% citrate (light-blue top) collection tubes. 25 mL of whole blood is required.
  • A normal control specimen must be drawn, processed and transported in a manner identical to the patient specimen.
  • Normal control must be free from known disease or hemostasis defect, and must be free of all medications known to interfere with aggregation (see list below).
  • Specimens must arrive at the UC Irvine Medical Center laboratory Monday through Friday between the hours of 9 a.m. and 2 p.m. The assay must be scheduled in advance.
  • Patient and control specimens must arrive at the medical center within 1.5 hours of collection. Specimens must remain at ambient temperature.

Patient and Specimen Requirements (All patients)

  • Platelet count - platelet count must be >100,000/mm3. If the platelet count is less than 100,000, have scheduler call during business hours to discuss alternatives at 714-456-5030.
  • Lipemia and hemolysis - Aggregation studies cannot be performed if sample is even slightly lipemic. Therefore, it is recommended that the patient’s diet be restricted to clear liquids for a minimum of 3 hours before collection. Hemolyzed specimens are not acceptable.
  • Transport temperature - Specimens must be transported at ambient temperature. Avoid exposure of the sample to ice, cold packs, extreme heat or extreme cold. Specimens must be received within 1.5 hours of collection.
  • Interfering medications – Patient and normal control should be free from interfering medications for at least 7 days. Interfering medications include:
    • Anti-inflammatory Drugs: Aspirin, indomethacin, naproxen, Pepto-Bismol, Alka-Seltzer, etc.
    • Anticoagulants: Dextran, heparin, prostacyclin.
    • Antibiotics: Ampicillin, azlocillin, carbenicillin, mithramycin, moxalactam, naficillin, nitrofurantoin, penicillin, piperacillin, ticarcillin.
    • Miscellaneous: Aminocaproic acid, ethanol, halothane, nitroglycerin, radiographic contrast agents.
    • Dietary supplements containing high doses of vitamin E or gingko biloba.