Platelet Disorders
Platelet Disorders

Platelet Disorders Diagnosis

Healthcare providers do not often screen for platelet disorders. If you have a routine blood test called a complete blood count (CBC), your healthcare provider may notice that you have a high or low platelet count. You may have this test during your yearly healthcare provider visit. Your provider may screen for platelet disorders if you have risk factors.

Your provider will diagnose a platelet disorder based on your physical exam and results from blood tests. They may order more tests to see whether another medical condition is causing your platelet disorder. You may have to see a hematologist, a doctor who specializes in treating blood disorders.

Physical exam

To diagnose a platelet disorder, your provider will ask about your medical and family history and do a physical exam to look for signs of a platelet disorder. They may do the following:

  • Feel your abdomen to see whether your spleen or liver is larger than normal.
  • Look at your eyes, nose, mouth, and skin for small, flat red spots called petechiae.
  • Look at your skin for bruising or purpura, which are red, purple, or brownish yellow spots on your skin.
  • Look for signs of other medical conditions that can cause platelet disorders.

Blood tests

Your provider will order one or more blood tests to diagnose your platelet disorder.

Complete blood count (CBC)

This test shows your platelet count and other blood cells in your blood.

Diagnosing high or low platelet counts  

Platelet count,

platelets per microliter
Normal platelet count 150,000 to 400,000
High platelet count More than 450,000

Low platelet count





Less than 150,000

100,000 to 150,000

50,000 to 100,000

Less than 50,000

Less than 20,000

Platelet disorders are grouped based on platelet count, which is the platelet count in a certain amount of blood.  

  • A normal platelet count is between 150,000 and 400,000 platelets per microliter of blood.
  • A high platelet count is more than 450,000 platelets per microliter of blood.
  • A low platelet count is less than 150,000 platelets per microliter of blood.
    • A low platelet count is mild if it is between 100,000 and 150,000 per microliter.
    • It is severe if it is less than 20,000 per microliter.

Peripheral blood smear

This test shows the number, size, and shape of your platelets and other blood cells. In a peripheral blood smear, a small amount of your blood is examined under a microscope. Results from this test can help your provider find the cause of your platelet disorder.

Other tests and procedures

Your provider may order other tests to find out which platelet disorder you have. These tests can also help find the cause of your condition.

  • Abdominal ultrasound are used to look for changes in your liver, spleen, and the lymph nodes in your abdomen.
  • ADAMTS13 testing checks the level of a protein called ADAMTS13 in your blood. Levels of this protein are very low in people who have thrombotic thrombocytopenic purpura.
  • Blood clotting tests check how well your blood is clotting.
  • Bone marrow tests can help your provider see whether your bone marrow is healthy and making new blood cells. They will look for a bone marrow disease that may be causing your platelet disorder.
  • Genetic testing checks for mutations , or changes, in genes that control how your body makes platelets or how well your platelets work.
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