What fibrinogen is
Fibrinogen is a circulating glycoprotein that polymerizes to fibrin during clotting. It's also an acute-phase reactant, produced by liver in response to IL-6 signaling during inflammation.
Optimal ranges
- Optimal: 200-350 mg/dL
- Reference: 200-400 mg/dL
- Elevated: >400 mg/dL
What raises it
- Chronic inflammation
- Smoking
- Obesity / metabolic syndrome
- Estrogen (oral contraceptives, pregnancy, oral HRT)
- Acute infection
- Diabetes
- Aging
What it predicts
- Cardiovascular events
- Stroke
- Venous thromboembolism (DVT, PE)
- Mortality
Independent predictor even after adjusting for other risk factors.
How to lower it
- Address inflammation
- Smoking cessation
- Weight loss
- Exercise
- Mediterranean-pattern diet
- GLP-1 therapy (modest reduction)
- Statins (modest reduction)
- Address sleep apnea
The clinical pearl: Fibrinogen adds resolution to cardiovascular risk assessment beyond standard markers. Elevated fibrinogen often signals chronic inflammation worth investigating.
Bottom line
Fibrinogen reflects clotting and inflammation. Elevated independently predicts cardiovascular events. Lowering through inflammation reduction and metabolic improvement.
200-350
mg/dL optimal fibrinogen
Both
clotting + inflammation marker
Independent
cardiovascular risk predictor