Maintaining adequate platelet levels is important for proper blood clotting and preventing excessive bleeding. A typical adult platelet range is 150,000 to 450,000 platelets per microliter of blood.

FIGURE 1. Platelet clumping (blue) was seen on peripheral blood smear. A misdiagnosis would have led to unnecessary tests and treatment. Ms. J, age 55 years, was referred to hematology for evaluation ...