Fibrinopeptide A is a substance released as part of the blood clotting process. A test can be done to measure the level of this substance in your blood.

Blood is 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.

No special preparation is necessary.

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

This test is used to help diagnose severe, abnormal clotting processes such as disseminated intravascular coagulation (DIC). Certain types of leukemia are associated with DIC.

Normal values differ from lab to lab. In general, the level of fibrinopeptide A should range from 0.6 to 1.9 nanograms per milliliter (ng/mL).

Increased fibrinopeptide A levels may indicate:

• DIC
• Leukemia at the time of diagnosis, during early treatment, and during a relapse
• Cellulitis
• SLE
• Some infections

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)