DefinitionThe platelet aggregation blood test checks how well platelets, a part of blood, clump together and cause blood to clot. How the Test is PerformedA blood sample is needed. The laboratory specialist will look at how the platelets spread out in the liquid part of the blood (plasma) and whether they form clumps after a certain chemical or drug is added. When platelets clump together, the blood sample is clearer. A machine measures the changes in cloudiness and prints a record of the results. How to Prepare for the TestYour health care provider may tell you to temporarily stop taking medicines that may affect the test results. Be sure to tell your provider about all the medicines you take. These include:
Also, tell your provider about any vitamins or herbal remedies you take. DO NOT stop taking any medicine without first talking to your provider. How the Test will FeelWhen the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or bruising. This soon goes away. Why the Test is PerformedYour provider may order this test if you have signs of a bleeding disorder or a low platelet count. It may also be ordered if a member of your family is known to have a bleeding disorder due to platelet dysfunction. The test can help diagnose problems with platelet function. It may determine whether the problem is due to your genes, another disorder, or a side effect of the medicine. Normal ResultsThe normal time it takes for platelets to clump depends on temperature, and may vary from laboratory to laboratory. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your provider about the meaning of your specific test results. What Abnormal Results MeanDecreased platelet aggregation may be due to:
RisksThere is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Taking blood from some people may be more difficult than from others. Other risks associated with having blood drawn are slight, but may include:
Note: This test is often performed because a person has a bleeding problem. Bleeding may be more of a risk for this person than for people without bleeding problems. ReferencesPai M, Moffat KA. Laboratory evaluation of hemostatic and thrombotic disorders. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 127. Rao AK, Songdej N, Di Paola JA. Platelet disorders and von Willebrand disease. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 41. Schafer AI. Approach to the patient with bleeding and thrombosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 162. | |
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Review Date: 2/2/2023 Reviewed By: Mark Levin, MD, Hematologist and Oncologist, Monsey, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |
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