Fibrinopeptide a

Alternative names 
FPA

Definition
This is a blood test that measures the level of fibrinopeptide a, which is a substance released as part of the clotting process. An elevated level may indicate an abnormal clotting process, such as disseminated intravascular coagulation (DIC).

How the test is performed

Blood is drawn from a vein, usually on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

The sample is then taken to the laboratory for examination.

How to prepare for the test
No special preparation is necessary.

For infants and children:
The preparation you can provide for this test depends on your child’s age and previous experiences. For specific information regarding how you can prepare your child, see the following topics:

     
  • infant test or procedure preparation (birth to 1 year)  
  • toddler test or procedure preparation (1 to 3 years)  
  • preschooler test or procedure preparation (3 to 6 years)  
  • schoolage test or procedure preparation (6 to 12 years)  
  • adolescent test or procedure preparation (12 to 18 years)

How the test will feel
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.

Why the test is performed
Measurement of fibrinopeptide a may help diagnose severe, abnormal clotting processes, such as disseminated intravascular clotting, that occur without generalized symptoms.

Certain types of leukemia are associated with DIC, and this test can help in the early detection of this severe complication.

Normal Values

The level of fibrinopeptide a should be in the range of 0.6 to 1.9 mg/ml.

Note: mg/ml = milligram per milliliter; The range of normal values varies between laboratories, and the laboratory performing the test should therefore be consulted for interpretation of the test result.

What abnormal results mean
Increased fibrinopeptide a levels may indicate:

     
  • DIC  
  • leukemia at the time of diagnosis, during early treatment, and during a relapse  
  • cellulitis  
  • SLE  
  • some infections

What the risks are
Risks associated with having blood drawn are slight:

     
  • excessive bleeding  
  • fainting or feeling light-headed  
  • hematoma (blood accumulating under the skin)  
  • infection (a slight risk any time the skin is broken)  
  • multiple punctures to locate veins

Special considerations
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.

Johns Hopkins patient information

Last revised: December 3, 2012
by Martin A. Harms, M.D.

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