Platform
Company
Complete Blood Count
Review status
Currently under review
Pending specialist review and validation.
This test measures how well your platelets clump together when exposed to adenosine diphosphate (ADP) in the laboratory. It is performed using light transmission, also called optical aggregometry, which is a standard method for assessing platelet function.
A sample of your blood is processed to obtain platelet rich plasma. As ADP is added, the instrument tracks changes in how much light passes through the sample. Those changes reflect how strongly and how quickly your platelets respond and stick to one another.
Results help investigate symptoms such as easy bruising, frequent nosebleeds, heavy menstrual bleeding, or unexpected bleeding during or after procedures. The test can help distinguish platelet function problems from issues with clotting proteins.
Clinicians also use ADP induced aggregation, alongside other agonists, to detect inherited platelet disorders, acquired dysfunction due to illnesses, and to assess the effect of antiplatelet medicines that target the P2Y12 receptor. It may be ordered before surgery or to help tailor antiplatelet therapy so your bleeding and clotting risks are balanced.
Lower than expected aggregation usually points to reduced platelet responsiveness. Common explanations include antiplatelet medications, low platelet count, recent transfusion, or an underlying platelet function disorder. Higher than expected aggregation can indicate increased platelet reactivity, which can influence clotting risk.
Your clinician will interpret this result together with tracings from other agonists, your complete blood count, medication history, and your symptoms. If findings are unexpected, you may be asked to repeat the test under controlled conditions, temporarily pause certain medicines when safe, or undergo additional studies such as testing with other agonists or genetic evaluation.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Medicines that block the P2Y12 receptor (for example clopidogrel, prasugrel, ticagrelor, cangrelor) directly lower ADP responses. Other agents such as some antidepressants, antibiotics, and herbal supplements can also blunt aggregation.
Light transmission aggregometry requires fresh platelet rich plasma. Delays to testing, excessive agitation, wrong anticoagulant ratio, or temperature extremes can alter platelet responses and produce misleading results.
Very low platelet counts reduce measurable aggregation, and abnormal hematocrit can change light transmission baselines. These factors are reviewed alongside the result to avoid misinterpretation.
Transfused donor platelets can mask an underlying defect or normalize an otherwise low response. Timing relative to transfusion is important when scheduling testing.
Alcohol, caffeine, and products such as fish oil, ginkgo, garlic, and high dose turmeric may affect platelet function. Follow pre-test instructions on fasting and supplements to improve accuracy.
Infection, inflammation, surgery, pregnancy, and kidney or liver disease can change platelet reactivity. Tell your care team about recent illnesses or physiological changes.
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