Platelet Tests Test
Platelet tests measure the number of platelets in your blood and how well they work to form clots. Platelets are small blood cells that help stop bleeding by forming clots.
What this test measures
Platelet tests include a platelet count test, which measures the number of platelets in your blood, and platelet function tests, which check your platelets' ability to form clots. Function tests may include closure time, viscoelastometry, platelet aggregometry, lumiaggregometry, flow cytometry, and bleeding time.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
A higher-than-normal platelet count (thrombocytosis) may be a sign of certain types of cancer, anemia, inflammatory bowel disease, rheumatoid arthritis, a viral or bacterial infection, or severe blood loss.
Lower-than-normal results
A lower-than-normal platelet count (thrombocytopenia) may be a sign of a cancer that affects the blood, a viral infection, an autoimmune disease, infection or damage to your bone marrow, cirrhosis, vitamin B12 deficiency, or gestational thrombocytopenia.
Frequently asked questions
What are platelets?
Platelets, also known as thrombocytes, are small blood cells that form in your bone marrow. They are essential for blood clotting.
What is the difference between a platelet count test and platelet function tests?
A platelet count test measures the number of platelets in your blood. Platelet function tests check your platelets' ability to form clots.
What does a low platelet count mean?
A low platelet count (thrombocytopenia) may be a sign of conditions like leukemia, viral infections, autoimmune disease, bone marrow damage, cirrhosis, or vitamin B12 deficiency.
What does a high platelet count mean?
A high platelet count (thrombocytosis) may be a sign of certain cancers, anemia, inflammatory bowel disease, rheumatoid arthritis, infection, or severe blood loss.
What are inherited platelet disorders?
Inherited platelet disorders are passed down from your family and include von Willebrand disease, Glanzmann thrombasthenia, Bernard-Soulier syndrome, and storage pool disease.
Related lab tests
Sources
- MedlinePlus: Platelet Tests — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.