Understanding Lab Tests for Thrombocytosis
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Thrombocytosis is a condition characterized by an abnormally high number of platelets in the blood. Platelets are essential for blood clotting, but when their levels become too elevated, it can increase the risk of blood clots forming inappropriately. A specific blood test is required to accurately diagnose this condition.
Recommended Test
Complete Blood Count / CBC (includes Differential and Platelets)
This comprehensive blood test directly measures platelet count along with other blood components. An elevated platelet count detected through this test is the primary indicator of thrombocytosis. The CBC also provides additional information about other blood cells that can help healthcare providers understand the underlying cause of the elevated platelets.
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Diagnosing Thrombocytosis
Thrombocytosis is often discovered during routine blood work, as many people with mildly elevated platelet counts may not experience obvious symptoms. When symptoms do occur, they can include headaches, dizziness, or unusual bleeding or bruising. A blood test that measures platelet count is essential for confirming the diagnosis and determining the severity of the condition.
Understanding Your Results
Normal platelet counts typically range from 150,000 to 450,000 platelets per microliter of blood. Thrombocytosis is generally diagnosed when platelet counts exceed 450,000. Your healthcare provider will interpret your results in the context of your overall health and may recommend additional testing to determine if the elevated platelets are due to an underlying condition or represent a primary blood disorder.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.
