Platelets are a type of blood cell that help control bleeding. If an injury occurs, platelets in the bloodstream rush to “plug up” the hole. Platelets do their job when you see a blood clot in a wound. Platelets are produced in the bone marrow and only live for a short time (just over a week). Too many platelets in the body, and you get blood that is “thick” or clots too much. Too few platelets, however, and you get “thin” blood that doesn’t clot quickly enough. Platelet counts are monitored via a complete blood count.