Platelet Function Assay (PFA) ADP/Collagen

Profile or Test Panel
Note: PFA values are only valid within certain platelet count and hematocrit ranges.
  • Platelet Function Assay (PFA) Profile
    (See panel below "Platelet Function Assay (PFA) Profile" for reference.)
  • Platelet Aggregation Study
Method Aggregation measured in CT (closure time)
Test Information The PFA is a screening test for platelet dysfunction. The cartridge membrane is coated with collagen, and with one of two platelet agonists (epinephrine or ADP). The platelets adhere to the collagen and aggregate in response to the collagen and epinephrine (or ADP). The response measured is known as the Closure Time (CT) and is reported in seconds. Depending on the results of this test, platelet aggregation testing may be necessary to establish the underlying cause.
Additional Test Information Test is affected by high or low platelet counts and anemia.  Samples with platelet counts >500,000/µl or <150,000/µl or samples with a hematocrit >50% or <35% may not give reliable results.
Results  may be normal in the setting of specific platelet disorders, including platelet storage pool deficiency and in mild VWD 
Sample Requirements Appointment required.  It will be drawn at Bloodworks Northwest.  Call Hemostasis Lab at 206-689-6594 to schedule an appointment
Requisition Form RFT- Hemostasis Reference Laboratory
Transaction Code 3245-01
CPT Codes 85576
Test Schedule Monday - Friday
Turn around Time (analytic time) Same day as scheduled visit
Report/ Results Fax number required to receive report