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Platelet Aggregation Study – Comprehensive

Justification

Comprehensive platelet aggregation studies should be included as part of initial bleeding workups to detect defects in platelet function. Platelets promote hemostasis by four interconnected mechanisms: 1) Adhering to sites of vascular injury or artificial surfaces, 2) Releasing compounds from their granules, 3) Aggregating together to form a hemostatic platelet plug and 4) Providing a procoagulant surface for activated coagulation protein complexes on their phospholipid membranes [2]. Since the activation of platelets is a multiphasic reaction involving different membrane bound receptors and intracellular signaling pathways, using multiple agonists at different concentrations is necessary to adequately assess platelet function and characterize abnormalities. This test can detect platelet function abnormalities associated with Glanzmann thrombasthenia, Bernard Soulier, von Willebrand Disease, ADP receptor defects, dense granule deficiency, and use of antiplatelet medications such as aspirin or Plavix.

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 Five 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
ALTERNATIVE - - - -
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 Function Assay, PFA
DESCRIPTION Platelet aggregation is measured in response to a panel of 7 different platelet agonists at multiple concentrations for a total of 11 determinations. Each agonist is tested individually against platelets suspended in platelet rich plasma (PRP) and platelet response measured by light transmittance aggregometry (LTA), the gold standard methodology for platelet functional testing. The agonists and concentrations included in this panel have been selected from those recommended by platelet aggregation testing guidelines published by the College of American Pathologists (CAP), Clinical and Laboratory Standards Institute (CLSI), North American Specialized Coagulation Laboratory Association (NASCOLA) and the British Society of Haematology.
LIMITATIONS Hemolytic, Icteric, and Lipemic samples
NORMAL RANGE Interpretation: Normal
ASSOCIATED TESTING -
REFERENCES

1. Hayward C et al. Development of North American consensus guidelines for medical laboratories that perform and interpret platelet function testing using light transmission aggregometry. Am J Clin Pathol 2010; 134:955-963.
2. Kottke-Marhcant K et al. The laboratory diagnosis of platelet disorders; an algorithmic approach. Arch Pathol Lab Med 2002; 126: 133-146.
3. Guidelines on platelet function testing: The British Society for Haematology BCSH Haemostasis and Thrombosis Task Force. J Clin Pathol. 1988; 41: 1322-1330.
4. Karon B et al. Platelet Function: Laboratory methods for evaluating effectiveness of anti-platelet therapy. Clinical Laboratory News. 2011; 37(4).
5. Lordkipanidze M et al. Evaluation of the platelet count drop method for assessment of platelet function comparison with “gold standard” light transmission aggregometry. Thromb Res 2009; 124(4): 418-422.
6. White MM et al. The use of the pint of care Helena ICHOR/Plateletworks and the Accumetrics Ultegra RPFA for assessment of platelet function with GPIIB-IIIa antagonists. J Thromb Thrombolysis 2004; 18(3): 163-169.
7. Jackson S. The growing complexity of platelet aggregation. Blood 2007 June 15;109(12).
8. CLSI. Platelet Function Testing by Aggregometry; Approved Guidelines. CLSI document H58-A. Wayne, PA: Clinical and Laboratory Standards Institute. 2008; 28(31).
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED -

Test Codes

ORDER CODE P3202
CPT CODE 85576x11
LOINC CODE 53568-2, 79188-9, 78522-0, 78527-9, 5995-6, 13592-1, 33550-5, 79130-1, 5998-0, 5996-4, 13592-1, 21027-8