What causes a decreased platelet count?

Several categories. 1. A false count due to platelet clumping 2. Destruction of platelets 3. Your body not making enough platelets #1 can be ruled out by having someone look at your blood smear. #2 can be caused by your immune system, medications, or an enlarged spleen. #3 can be from a problem with your bone marrow (leukemia, lymphoma, fibrosis), a nutritional deficiency, drug, or toxin. Lots of causes! See a doc.
Error, prodctn, distru. A random low platelet count is often the result of the nature of the test. Platelets are frail & may clump in the specimen before the test is run so a falsely lowered count is found. Low production during illness or bone marrow failure usually shows up in several blood cells. Increased destruction by immune factors or loss with bleeding disorders are seen. Platelets only last a few days at best.