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Fibrinogen
Definition
Fibrinogen is a protein produced by the liver. This protein helps stop bleeding by helping blood clots to form. A blood test can be done to tell how much fibrinogen you have in the blood.
Alternative Names
Serum fibrinogen; Plasma fibrinogen; Factor I; Hypofibrinogenemia test
How the Test is Performed
A blood sample is needed. For information on how this is done, see: Venipuncture
How to Prepare for the Test
There is no special preparation needed.
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
Your doctor may order this test if you have problems with blood clotting, especially if you have excessive bleeding.
Normal Results
The normal range is 200 - 400 milligrams per deciliter (mg/dL).
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
What Abnormal Results Mean
Abnormal results may be due to:
- Excessive fibrinogen use (as in disseminated intravascular coagulation)
- Fibrinogen deficiency (from birth, or acquired after birth)
- Fibrinolysis
- Hemorrhage
The test may also be performed for placenta abruptio.
Risks
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood 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)
Note: This test is most often performed on people who have bleeding disorders. The risk of excessive bleeding is slightly greater in such people than for those who do not have bleeding problems.
References
Gailani D, Neff AT. Rare coagulation factor deficiencies. In: Hoffman R, Benz EJ Jr., Shattil SJ, et al, eds. Hoffman Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingstone Elsevier; 2008:chap 127.
Kessler C. Hemorrhagic disorders: Coagulation factor deficiencies. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 180.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
