The tests used to find low platelet count include physical examination, blood tests and ultrasound, states Healthline. Other tests for low platelet count are bone marrow aspiration and biopsy.
A physical examination involves checking the patient's body for excessive bruising or petechiae, explains Healthline. A doctor also checks for an enlarged spleen, which can cause a low platelet count, by feeling the patient's abdomen. In addition, the doctor may review a patient's family history for bleeding disorders to determine if the bleeding is hereditary.
Doctors perform a complete blood count test, which helps determine the quantity of blood cells in the body, claims Healthline. Blood tests also involve testing for platelet antibodies to determine if a low platelet count is medication induced as a result of taking certain medications such as quinine. These antibodies destroy blood platelets.
Blood-clotting tests, which include partial thromboplastin time and prothrombin time, are other methods that a doctor uses to find low platelet count, notes Healthline. These tests involve adding certain chemicals to a blood sample to establish the length of time blood takes to clot.
Ultrasound involves the use of sound waves to produce a picture of the spleen, according to Healthline. The picture helps the doctor determine if the spleen is enlarged or not.