Fibrinogen
- Sample Type
- Plasma
- Fasting
- No
- Unit
- mg/dL
Function
Fibrinogen, also known as Factor I, is a glycoprotein produced by the liver that plays a central role in the blood coagulation cascade. When a blood vessel is injured, the enzyme thrombin converts fibrinogen into fibrin. Fibrin molecules then link together to form a mesh-like structure that traps platelets and red blood cells, creating a stable blood clot. Without adequate fibrinogen, the body cannot effectively stop bleeding.
Why it is Ordered
The fibrinogen test is typically ordered as part of a workup for bleeding disorders or abnormal clotting events. It is used to investigate a prolonged Prothrombin Time (PT) or Activated Partial Thromboplastin Time (aPTT). It is also vital in emergency settings to screen for Disseminated Intravascular Coagulation (DIC), a life-threatening condition where the body's clotting factors are rapidly consumed.
Associated Conditions
- Liver Disease: Since the liver produces fibrinogen, cirrhosis or hepatitis can lead to low levels.
- DIC: Characterized by widespread clotting followed by severe bleeding due to factor depletion.
- Acute Phase Response: Fibrinogen levels rise during systemic inflammation, infection, or after major surgery.
- Afibrinogenemia: A rare genetic condition where fibrinogen is completely absent.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
Fibrinogen levels are highly sensitive to acute physiological stress. High levels can be found during pregnancy, cigarette smoking, or even intense exercise, which may mask an underlying issue. Conversely, recent blood transfusions can provide a false sense of a patient's own fibrinogen production. Interpretation also depends on the specific assay used (Clauss vs. Derived), so if results don't match the clinical picture of bleeding, a re-test using a different method is often warranted.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Fibrinogen:
Official Sources
Research & Guidelines
- PubMed: Fibrinogen Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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