Fibrinogen
A clotting protein that also rises with inflammation and contributes to cardiovascular risk.
| Typical reference range | 175–425 mg/dL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Fibrinogen is made by the liver and converted to fibrin to form blood clots. It is also an acute-phase protein that increases with inflammation.
Why it matters
Elevated fibrinogen increases blood viscosity and clot formation and is an independent predictor of cardiovascular disease. Low fibrinogen causes bleeding risk.
What a high result can mean
High levels occur with inflammation, infection, smoking, obesity, diabetes, pregnancy, oral contraceptives, older age and inactivity.
What a low result can mean
Low levels occur with severe liver disease, disseminated intravascular coagulation, inherited fibrinogen disorders and certain medications (thrombolytics, asparaginase).
What affects the result
Acute illness raises it temporarily. Quitting smoking, exercise and weight loss lower it. Interpret with hs-CRP and lipid markers.
Units and conversion
Usually reported in mg/dL.
- From g/L: multiply by 100 to get mg/dL
- From umol/L: multiply by 34 to get mg/dL
Also called on lab reports
Fibrinogen Activity, Fibrinogen Antigen, Fibrinogen, Clauss
Related tests: Inflammation & Immunity
This page is educational and does not replace advice from a healthcare professional.