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Platelet Count


Platelets or clotting cells are the smallest type of blood cell. They are formed in the bone marrow and are important in blood clotting. When bleeding occurs, the platelets swell, clump together and form a sticky plug (a clot) which helps stop the bleeding.

What might a low result mean?

A low platelet count is called thrombocytopenia and can be mild or severe. Low platelets may make you prone to bruising or uncontrolled bleeding. Low platelets can be caused by the bone marrow producing too few platelets, or by the body destroying them faster than they can be produced e.g. in an autoimmune condition. Low platelets can also be caused by certain medications, by nutritional deficiencies such as iron, vitamin B12 and folate, some viral infections as well as alcoholism and liver disease. Pregnancy can also cause platelets to be mildly low.

What might a high result mean?

A high platelet count is called thrombocythemia or thrombocytosis and occurs when the bone marrow produces too many platelets. Raised platelets can be caused by a bone marrow disorder, or can be the result of infection, inflammation, iron deficiency anaemia, recent trauma or blood loss.