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.
Lab error or real. The platelets are fragile & subject to clumping in the specimen& that drops the count. Repeating a level would be prudent on a random low count. True low counts come from decreased production (illness, bad bone marrow, cancer) or increased loss/destruction (disease, bleeding disorder).