What Is Fibrinogen?
Fibrinogen is a protein made by the liver that plays a central role in blood clot formation. When a blood vessel is damaged, fibrinogen is converted into fibrin to form a clot. It is also an acute-phase reactant — levels rise during inflammation or infection.
Normal Fibrinogen Range
| Result | Range |
|---|---|
| Normal | 200–400 mg/dL |
| Low (hypofibrinogenaemia) | Below 150 mg/dL |
| High | Above 400 mg/dL |
Causes of High Fibrinogen
- Active inflammation or infection
- Cardiovascular disease (high fibrinogen is an independent risk factor)
- Pregnancy
- Smoking
- Obesity and metabolic syndrome
- Stroke risk — high fibrinogen thickens blood
Causes of Low Fibrinogen
- Disseminated intravascular coagulation (DIC) — fibrinogen consumed rapidly
- Severe liver disease — impaired production
- Congenital afibrinogenaemia (rare genetic condition)
- Massive transfusion or bleeding
Fibrinogen and Cardiac Risk
Elevated fibrinogen (above 400 mg/dL) is associated with increased risk of heart attack and stroke — it promotes clot formation and inflammation in arterial walls.
FAQs
Is fasting required?
No fasting needed for a fibrinogen test.
Can I lower my fibrinogen naturally?
Regular aerobic exercise, quitting smoking, losing excess weight and reducing inflammation can help lower elevated fibrinogen.
What drugs affect fibrinogen?
Statins, fibrates, and some other medications can lower fibrinogen levels.
Medical Disclaimer: Fibrinogen results should be interpreted alongside clinical history and other clotting tests by your doctor.