How is a low platelet count diagnosed?
Investigation usually starts with a history of symptoms, signs of bleeding or bruising, other medical problems, recent infections and medications. A blood test is then taken. In the haematology lab the doctor: • performs a full blood count • examines the blood film under a microscope (see Figure 1) • examines the blood sample in the test tube. Usually, another full blood count sample is requested to confirm the result and see if it is a persisting abnormality. Depending upon the severity of the platelet lack and the likely cause, the person is likely to be referred to a haematologist at the hospital. If the platelet count is very low, the person may need to be seen on the same day, and have a bone marrow test performed. A bone marrow test is done under local anaesthetic, with samples usually taken from the back of the pelvis. This test helps the haematologist to decide if platelets are being produced normally and whether the rest of the bone marrow appears normal. Further tests such as
