Definition
- Fibrinogen is a glycoprotein synthesized in the liver. It is modified by thrombin to become fibrin, a visible clot. It is also an acute-phase reactant.
- Normal range: 150 " “400 mg/dL (most abundant circulating clotting factor).
Use
- This test detects decreased or abnormal fibrinogen.
- It may be used to determine the severity and evolution of DIC by performing serial determinations.
- Because of the initial elevation of fibrinogen, its determination is not useful in the diagnosis of DIC.
Interpretation
- Severe fibrinogen deficiency may prolong PT, PTT, and TT.
Increased In "
" Increased fibrinogen thought to contribute to thrombophilia. ‚
- Acute inflammatory/infectious processes
- Cancer
- Pregnancy and use of oral contraceptives
- Older age
- Early DIC
Decreased In
- Congenital afibrinogenemia or hypofibrinogenemia.
- Dysfibrinogenemia (congenital or acquired).
- DIC and pathologic fibrinolysis. Fibrinogen is consumed after initial elevation as an acute-phase reactant.
- Very advanced liver disease.
Limitations
Preanalytic
- Clotted specimens or those obtained with the wrong anticoagulant
- Inappropriately filled test tubes
- Inappropriately stored blood
- Hyperlipidemic, icteric, or hemolyzed blood
- Hct >55%