Fibrinopeptide A

Definition

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.

Alternative Names

FPA

How the test is performed

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.

How to prepare for the test

No special preparation is necessary.

How the test will feel

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.

Why the test is performed

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

Normal Values

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

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Increased fibrinopeptide A levels may indicate:

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

What the risks are

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)

References

Schafer AI. Hemorrhagic disorders: disseminated intravascular coagulation, liver failure, and vitamin K deficiency. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 181.