Introduction

• Fibrinogen (Factor I) is produced by the liver and is essential for blood clot formation.
• Important for diagnosing and managing bleeding and clotting disorders.

Structure and Function

• Composed of three pairs of chains (Aα, Bβ, γ).
• Forms fibrin for blood clotting and aids in wound healing.
• Promotes platelet aggregation and inflammatory cell influx.

Regulation of Fibrinogen Levels

• Normal levels: 200-400 mg/dL.
• Produced more during inflammation (acute phase protein), stimulated by IL-6.
• Estrogen increases fibrinogen, while testosterone inhibits it.
• Liver dysfunction can lower fibrinogen, causing bleeding issues.
• Genetic mutations can cause afibrinogenemia or dysfibrinogenemia.

Clinical Significance of Fibrinogen

• Bleeding Disorders: Low or dysfunctional fibrinogen leads to bleeding problems (e.g., afibrinogenemia).
• Thrombotic Disorders: High fibrinogen increases clotting risks (e.g., DVT, PE) and is linked to inflammation and metabolic issues.
• As a Biomarker: Elevated fibrinogen indicates inflammation and may predict heart disease, cancer, and clotting risks.