Parts of the Blood

Blood is made up of red blood cells, which we've read about in the previous sections, white blood cells and platelets.

White blood cells, also known as leukocytes, fight off infection within the body. The normal range is 4,500-10,000 per microliter (mcL).

Platelets are responsible for clotting in the blood. A low number of platelets can cause a risk of bleeding. The normal range is 150,000-400,000 microliter (mcL).

Read about what tests are included in a Complete Blood Count.