Fibrinogen: What Your Result Means
Result guide · Coagulation
Content last reviewed 2026-09-12 · Educational information — not medical advice
Quick answer
Fibrinogen is a clotting protein made by the liver and converted to fibrin to form a clot. High levels reflect inflammation (it is an acute-phase protein); low levels raise concern for liver disease, severe bleeding, or a rare clotting disorder.
What is Fibrinogen?
Fibrinogen is the precursor to fibrin, the mesh that holds a clot together. The liver produces it, and levels rise with inflammation and fall with liver failure, massive bleeding, or consumption during abnormal clotting (DIC). It is measured alongside PT/INR, aPTT, and D-dimer when a clotting problem is suspected.
Typical reference interval: Commonly about 200–400 mg/dL; laboratories publish their own range.. Laboratories differ — the interval printed on YOUR report always governs.
If your Fibrinogen is high
Common reasons Fibrinogen runs above the reference interval:
- Inflammation or infection — fibrinogen is an acute-phase protein and rises with the inflammatory response
- Pregnancy — physiologically higher
- Smoking and obesity — chronic low-grade inflammation raises levels
- Tissue injury or cancer — can elevate fibrinogen
If your Fibrinogen is low
Common reasons Fibrinogen runs below the reference interval:
- Liver disease — the liver makes less fibrinogen
- Disseminated intravascular coagulation (DIC) — fibrinogen is consumed faster than it is replaced — an emergency
- Massive bleeding — lost and consumed during hemorrhage
- Inherited deficiency — rare disorders such as afibrinogenemia
- Certain drugs — thrombolytics and some anticoagulants can lower it
Symptoms worth knowing
Fibrinogen itself causes no symptoms; abnormal bleeding or clotting — bruising, bleeding gums, blood clots — reflects the underlying problem.
What usually happens next
Get your Fibrinogen checked
These lab tests measure Fibrinogen directly. Ordering online takes a few minutes and results arrive securely.
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Related result guides
Frequently asked questions about Fibrinogen results
What causes low fibrinogen?
Liver disease, massive bleeding, or consumption during abnormal clotting (DIC). A low fibrinogen with bleeding is an emergency.
Is high fibrinogen dangerous?
It usually reflects inflammation rather than a clotting disorder; persistent elevation is a cardiovascular risk marker and is interpreted in context.
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