Diagnosis

During an exam for a routine physical or another condition, your doctor might find that your spleen is enlarged or you have signs or symptoms of an infection or another condition. In that case, your doctor might order a complete blood count. This test can determine whether your platelet count is higher than normal.

Because a number of conditions can cause a temporary rise in your platelet count, your doctor likely will repeat the blood test to see if your platelet count remains high over time.

Your doctor might also order tests to check for:

• Abnormal levels of iron in your blood
• Markers of inflammation
• Undiagnosed cancer
• Associated gene mutations

You might also need a procedure that uses a needle to remove a small sample of your bone marrow for testing.