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Platelet Aggregation – Aspirin Sensitivity


Aspirin (acetylsalicylic acid) is commonly prescribed as an antiplatelet agent for the prevention of arterial thrombosis in conjunction with Plavix. Aspirin is a COX-1 inhibitor and reduces the production of thromboxane A2 (TXA2), a vasoconstrictor and activator of platelets, in activated platelets, interrupting the positive feedback loop. Aspirin sensitivity testing by platelet aggregometry can be used to assess the effectiveness of platelet inhibition by aspirin therapy or restoration of platelet function after discontinuation of aspirin.

STAT: < 24 hours (M-F)

Light Transmittance Aggregometry (LTA)

Draw Tube: Blue Top

Sample Type: Citrated Whole Blood

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED Citrated Whole Blood Four tubes, 3mL each (or equivalent volume) For pediatric minimum, please call (800) 566-3462. Room Temperature: 4 hours
By appointment only - must arrive at lab within 2 hours of draw
REJECTION CRITERIA Samples received more than 2 hours after draw
SPECIAL INSTRUCTIONS See Draw Guide By appointment only

General Information

METHODOLOGY Light Transmittance Aggregometry (LTA)
STAT TAT < 24 hours (M-F)
STAT TAT Performance > 90% of results released in 24 hours
ROUTINE TAT < 24 hours (M-F)
ALTERNATIVE NAMES Platelet Aggregation - ASA, Aspirin Sensitivity
DESCRIPTION Platelet aggregation is measured in response to Arachidonic Acid and control agonists by light transmittance aggregometry (LTA). A significant reduction in platelet aggregation in response to Arachidonic Acid is expected with successful aspirin therapy.
LIMITATIONS Hemolytic, Icteric, and Lipemic samples
NORMAL RANGE Interpretation
SAMPLE REPORT Upon request

Test Codes

CPT CODE 85576x4
LOINC CODE 53568-2