A platelet is the smallest type of blood cell. Platelets are the body's first defense against bleeding, helping the blood to clot (coagulate) by collecting at the site of a wound and clumping together to help stop the flow of blood.

People with very low levels of platelets or who have bleeding disorders may need to have transfusions of platelets to prevent excessive bleeding.

Current as of: September 9, 2014

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Joseph O'Donnell, MD - Hematology, Oncology