Platelet Count – Whole Blood is used to detect the number of platelets in the blood ,type of cells that are essential for normal blood clotting. Platelets are tiny fragments of cells that are essential for normal blood clotting. A platelet count may be used to screen for or diagnose various diseases and conditions that can cause problems with clot formation. It may be used as part of the workup of a bleeding disorder, bone marrow disease, or excessive clotting disorder