This test measures the number of platelets present in a microliter of your blood. Platelets are a type of blood cells that help the blood to clot. In case of an injury, the platelets clump together and form a clot to repair the damage and stop bleeding. If you do not have an adequate quantity of platelets in your blood, you may suffer from excessive bleeding. This test may be performed to monitor known conditions such as thrombocytopenia (lower than the normal number of platelets), thrombocytosis (higher than the normal number of platelets), bleeding disorders, some type of blood cancers, certain infections, certain autoimmune diseases, etc. Your doctor may advise you to undergo this test if you experience any signs and symptoms such as nosebleeds, gum bleeding, rectal bleeding, blood in the stool or urine, excessive bleeding when injured, dizziness or lightheadedness, fainting, chest pain, headache, vision changes, redness or burning pain in the hands and feet, headache, tingling or numbness of hands and feet, etc. Your doctor may also advise you to undergo this test on a regular basis if you have a family history of bleeding disorders. This test may also be performed as a part of a complete blood count test panel to monitor the overall health of an individual. ### Frequency of Testing: If you have a family history of bleeding disorders, your doctor may ask you to perform this test on a 6-monthly basis or a yearly basis. If you are an otherwise healthy individual above the age of 35 years, your doctor may advise you to undergo this test on a yearly basis or every other year. ### What does your test result mean? If the test result falls within the normal reference range, you have an adequate amount of platelets in the blood and hence, no medical intervention is necessary. Lower than the normal levels of platelet count is known as thrombocytopenia. This may occur due to medical conditions such as leukemia (a type of blood cancer), aplastic anemia, viral infections, some autoimmune disorders, splenomegaly (an enlarged spleen), cirrhosis of the liver, kidney dysfunction, etc. Other factors such as chemotherapy drugs (cancer medicines); vitamin B12, iron, or folic acid deficiency; chronic alcohol use, etc. may also cause thrombocytopenia. Higher than the normal levels of platelet count is known as thrombocytosis. Thrombocytosis is categorized as primary or essential thrombocytosis and secondary thrombocytosis. Primary thrombocytosis is an uncommon disorder; it generally occurs in individuals greater than 50 years of age, especially in women. It occurs when your bone marrow produces too many platelets. Secondary thrombocytosis may occur due to an ongoing disease condition, certain infections, cancer, anemia, major surgery or trauma, removal of the spleen, etc. If you have higher or lower than normal levels of platelets, consult your doctor for further instructions. Based on the test results, your doctor may advise appropriate medical treatments, lifestyle modifications, or further diagnostic tests.