The reference range is a normal biphasic pattern of aggregation in response to specific platelet activators (see image below).
Decreased platelet aggregation may be associated the following:
Fibrin degradation products
Drugs that block platelet formation (eg, thiazide diuretics, interferon, alcohol)
Specifics for collection and panels are outlined as follows:
Specimen type: Whole blood
Container: Vacutainer, light blue (citrate)
Collection method: Venipuncture
Specimen volume: 4 mL
See the list below:
Four tubes are needed for platelet aggregation testing.
Seven tubes are required for full aggregation and secretion testing.
Process whole blood specimens within 4 hours of collection.
Store specimens at room temperature (cooling may lead to activation).
Related tests: Complete blood count, platelet count, prothrombin time (PT); partial thromboplastin time (PTT), bone marrow biopsy, coagulation factors, von Willebrand factor (VWF)
Platelet aggregation studies test the clumping response of platelets to various platelet activators (eg, ADP, collagen, arachidonic acid, thrombin, epinephrine, ristocetin) as continuously recorded by a light transmission aggregometer. With some aggregometers, the secretion of platelet granules, another indicator of platelet function, may also be evaluated simultaneously by measuring the release of ATP by the aggregating platelets. Platelet secretion defects can provide greater diagnostic sensitivity than platelet aggregation testing alone. [1, 2, 3]
Conditions associated with decreased platelet aggregation include suspected hereditary and acquired disorders of platelet function. Indications for platelet aggregation studies include the following:
Diagnostic evaluation of excessive bleeding or bruising
Monitor the effectiveness of antiplatelet medication
Detect aspirin resistance
Monitor platelet function during complex surgical procedures
Screen at-risk presurgical patients
Medications (including over-the-counter medications) that may affect platelet aggregation results include the following:
Antibiotics (penicillins, cephalosporins, nitrofurantoin)
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Healthcare providers should ask patients about any of these medications that may have been taken within 2 weeks before testing.
Burris CA, Ashwood ER, Burns DE. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th ed. St. Louis: Elsevier Saunders; 2006. 1633:962-967.
McPherson RA, Matthew R. Pincus MR. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia: Elsevier Saunders; 2011. 254-5.
Wallach J. Interpretation of Diagnostic Tests. 6th ed. New York: Little, Brown; 1996. 717.
Arbel Y, Birati EY, Finkelstein A, Halkin A, Kletzel H, Abramowitz Y, et al. Platelet inhibitory effect of clopidogrel in patients treated with omeprazole, pantoprazole, and famotidine: a prospective, randomized, crossover study. Clin Cardiol. 2013 Jun. 36(6):342-6. [Medline].
Christopher P Kellner, MD Resident Physician, Cerebrovascular Research Laboratory, Department of Neurological Surgery, Columbia University Medical Center, New York Presbyterian Hospital
Disclosure: Nothing to disclose.
Thomas M Wheeler, MD Chairman, Department of Pathology and Immunology, WL Moody, Jr, Professor of Pathology, Professor of Urology, Baylor College of Medicine
Thomas M Wheeler, MD is a member of the following medical societies: Alpha Omega Alpha, American Association for Cancer Research, American Medical Association, American Society for Clinical Pathology, American Society of Cytopathology, American Thyroid Association, American Urological Association, College of American Pathologists, United States and Canadian Academy of Pathology, International Society of Urological Pathology, Harris County Medical Society
Disclosure: Received stock from PathXL for medical advisory board. for: PathXL, Inc.
Judy Lin, MD
Disclosure: Nothing to disclose.
Research & References of Platelet Aggregation |A&C Accounting And Tax Services