Platelet Count: What High or Low Platelets Mean

Platelets are small cell fragments made in the bone marrow that clump together to seal damaged blood vessels. The CBC reports how many circulate per liter of blood.

Platelet count is often read alongside MPV (mean platelet volume), which hints at whether circulating platelets are young and large or older and smaller.

Low platelets can mean easy bruising, nosebleeds, or heavier periods. Common causes include viral infection, alcohol, liver disease, certain medications, and immune conditions.

High platelets most often reflect inflammation, iron deficiency, or recovery from bleeding. Persistently high counts without an obvious trigger are worth a hematology opinion.

Recent infection, inflammation, iron deficiency, alcohol intake, pregnancy, spleen size, and medications such as heparin and some antibiotics affect the count. Clumping in the tube can also cause a falsely low result.