PLATELET FUNCTION SCREEN

Mnemonic

PFA

Synonym

PFA - Bleeding Time, Platelet Function Assay

Guidelines

The Platelet Function Screen does not necessarily predict bleeding at surgery. An abnormal test result may not be associated with excessive bleeding. Conversely, a normal test result may exist in the setting of interaoperative or post surgical bleeding.

Patients with low hematocrits (<35%) or low platelet counts (<150,000) may show falsely abnormal platelet function with this test method. Patients with hematocrits <35% or platelet counts less than 150,000 may exhibit prolonged results. Platelet inhibiting drugs, such as aspirin, and anti-glycoprotein IIb/IIIa antagonists directly affect platelet function. Certain dietary fatty acids and lipids are known to inhibit platelet function. Hemolysis and an elevated erythrocyte sedimentation rate (ESR) may interfere with results.

Specimen Collection Requirements

Collect

Whole Blood, (2) light blue 3 mL (3.2% Buffered Sodium Citrate) top tubes OR (3) light blue 2 mL (3.2% Buffered Sodium Citrate) top tubes; must use 21G or larger needle

Handling

DO NOT CENTRIFUGE SPECIMEN. Specimens MUST be walked down to the lab; do not use tube system for transport.

Preferred Volume

Whole Blood, (2) light blue 3 mL (3.2% Buffered Sodium Citrate) top tubes OR (3) light blue 2 mL (3.2% Buffered Sodium Citrate) top tubes

Minimum Volume

Whole Blood, (1) light blue 3 mL (3.2% Buffered Sodium Citrate) top tubes OR (2) light blue 2 mL (3.2% Buffered Sodium Citrate) top tubes

Transport

Sample must be transported in an upright position without disruption. Do NOT transport sample via pneumatic tube system. It must be received in the Good Samaritan Regional Medical Center Hematology Lab within 2 hours of collection. All samples must be transported STAT directly to the Good Samaritan Regional Medical Center Hematology Lab. The laboratory should also be notified of the transport at 541-768-5059.

Rejection Criteria

Clotted samples, samples collected in containers other than 3.2% buffered sodium citrate, tubes filled less than 90%, samples from patients with a Hematocrit greater than 55%, hemolyzed samples due to ex-vivo causes (i.e., difficult draw, poor sample draw), whole blood samples that were frozen before processing

Stability

Ambient: 4 hours

Testing Information

Performed

GSRMC, 7 days a week

Method

Whole blood platelet adhesion and platelet aggregation

Referral Lab

Samaritan Health Services Laboratories

Reference Values

Reference Values

COL/EPI Borderline:
153-170 seconds
COL/ADP Borderline:
108-120 seconds

COL/EPI: 80-152 seconds
COL/ADP: 53-107 seconds
TEST INTERPRETATIONS
(Most Common):

Normal Platelet Function
COL/EPI Normal
COL/ADP Normal

Consistent with drug-induced platelet dysfunction
COL/EPI Abnormal
COL/ADP Normal

Intrinsic platelet dysfunction; further studies are indicated
COL/EPI Abnormal
COL/ADP Abnormal

NOTE: Other interpretive comments may be used as test results indicate.

CPT Codes

85576

Last Updated: Tuesday, April 14, 2020 12:36:08 PM