[Laboratory procedures following thrombocytopenia diagnosis]

Thrombocytopenia--decrease in the blood platelets count below 100 x 10(9)/L--may represent a significant clinical complication--bleeding. A risk of haemorrhagic complications increases with the severity of thrombocytopenia. Even severe thrombocytopenia, however, may be a sign of a condition with predominant symptoms of thrombosis where bleeding is on the background (thrombotic microangiopathy, for example) or where bleeding occurs concurrently with symptoms of thrombosis (so called thrombohaemorrhagic syndromes). It is necessary to exclude pseudothrombocytopenia when thrombocytopenia is first diagnosed. It is then recommended to follow a standardized differential diagnosis algorithm that should be available at each clinical site. We summarize the general rules of thrombocytopenia differential diagnosis with a specific focus on laboratory processes.