Platelet function tested by

(A) Bleeding time # Most important screening tests of the primary hemostatic system are> Bleeding time (a sensitive measure of platelet function), and a platelet count.> Latter correlates well with the propensity to bleed. The normal platelet count is 150,000 to 450,000/mL of blood. As long as the count is > 100,000/mL, patients> are usually asymptomatic and the bleeding time remains normal.> Platelet counts of 50,000 to 100,000/mL cause mild prolongation of the bleeding time; bleeding occurs only from severe trauma or other stress.> Patients with platelet counts 50,000/pL have easy bruising, manifested by skin purpura after minor trauma and bleeding after mucous membrane surgery. Patients with a platelet count 20,000/pL have an appreciable incidence of spontaneous bleeding, usually have petechiae, and may have intracranial or other spontaneous internal bleeding