Ferritin is a protein found inside cells that stores iron so your body can use it later. A ferritin test indirectly measures the amount of iron in your blood.

The amount of ferritin in your blood (serum ferritin level) is directly related to the amount of iron stored in your body.

This test measures the amount of iron in the body. Iron is important for red blood cell production.

Additional conditions under which the test may be performed:

• Anemia of chronic disease

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

Your doctor may tell you to stop taking any drugs that may affect the test results.

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.