Fibrinogen
Fibrinogen is the soluble precursor of fibrin — the protein that physically forms a blood clot. It's also a positive acute-phase reactant, so it rises in inflammation and falls in consumption coagulopathies.
What it measures
Fibrinogen is produced by the liver and is the substrate that thrombin converts into fibrin at the final step of the clotting cascade. Two clinical narratives matter most: (1) dropping fibrinogen in a bleeding patient is the classic disseminated intravascular coagulation (DIC) signal — clotting factors are being consumed faster than the liver can make them; (2) rising fibrinogen is part of the acute-phase response (alongside CRP) and tracks chronic inflammation and cardiovascular risk. The level alongside D-dimer + platelets + PT/INR is the standard DIC panel.
What a high value can mean
- Acute-phase reaction — infection, inflammation, surgery, trauma; fibrinogen rises with CRP.
- Chronic inflammation, autoimmune disease — rheumatoid arthritis, vasculitis.
- Cardiovascular risk marker — independently elevated in atherosclerosis and post-MI; high fibrinogen amplifies LDL-driven risk.
- Pregnancy, oral contraceptives — physiological/pharmacological rise.
- Malignancy — paraneoplastic elevation.
What a low value can mean
- Disseminated intravascular coagulation (DIC) — sepsis, obstetric emergencies, massive trauma; consumed faster than synthesised.
- Severe liver disease — hepatic synthesis fails (decompensated cirrhosis).
- Congenital afibrinogenaemia or dysfibrinogenaemia — rare inherited.
- Thrombolytic therapy — tPA / streptokinase clear fibrinogen.
- Asparaginase chemotherapy — disrupts liver protein synthesis.
When to discuss with a doctor
A low fibrinogen in a bleeding patient is an emergency — typically managed by replacement (cryoprecipitate or fibrinogen concentrate) alongside the underlying cause. Asymptomatic elevation is most often just inflammation and doesn't change immediate management, but as a CV risk factor it adds weight to lipid-lowering decisions. Mediora.AI shows fibrinogen with the rest of the coagulation panel; bleeding management is emergency-medicine territory.