What Does a High White Platelet Count Mean?
Medical Author: Benjamin Wedro, MD, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD
Ask the experts: What are some of the potential diagnoses when a person has a high platelet count? (Platelet count approximately 420?)
Doctor's response: Platelets are the smallest cell-like structures in the bloodand are important for blood clotting and plugging damaged blood vessels. Platelet counts are usually done by laboratory machines that also count other blood elements such as the white and red cells. Normal platelet counts are in the range of 150,000 to 400,000 per microliter (or 150 - 400 x 109 per liter), but the normal range for the platelet count varies slightly among different laboratories.