What is the function of fibrinogen?
Fibrinogen (P-Fibrinogen) is a glycoprotein synthesized in the liver and is a crucial component of the blood coagulation system. It functions as a precursor to fibrin and is activated upon injury to blood vessels, where it is converted into insoluble fibrin threads that form a stable blood clot and prevent bleeding. In addition to its role in hemostasis, fibrinogen is an acute phase reactant, meaning that its levels can increase during inflammation and other disease states. Imbalances in fibrinogen levels can affect both coagulation capacity and the systemic inflammatory response.
What is fibrinogen?
Fibrinogen consists of three polypeptide chains – alpha (α), beta (β) and gamma (γ) – that form a complex structure with two identical units linked by disulfide bridges. These chains enable fibrinogen's role in coagulation, where the enzyme thrombin cleaves fibrinogen into fibrin monomers that are then polymerized into a fibrin network. This process is further stabilized by factor XIII, leading to the formation of a strong and durable blood clot.
In addition to its role in hemostasis, fibrinogen is an acute phase reactant, meaning that its levels can increase during inflammation, infection, and other disease states. Imbalances in fibrinogen levels can affect both coagulation ability and the systemic inflammatory response. Elevated levels are linked to an increased risk of cardiovascular disease, blood clots, and chronic inflammation, while low levels may indicate liver failure, coagulation disorders, or disseminated intravascular coagulation (DIC).
Why is P-Fibrinogen analyzed?
The P-Fibrinogen blood test is used to assess the blood's clotting ability and identify underlying diseases that affect fibrinogen production. Since fibrinogen is a central part of the coagulation system and at the same time an acute phase reactant, elevated or decreased levels can provide important information about both coagulation disorders and inflammatory processes.
- Suspected blood clots (thrombosis) or other coagulation disorders.
- Investigation of inflammatory conditions, since fibrinogen increases in systemic inflammation.
- Assessment of cardiovascular disease, where elevated fibrinogen levels are linked to an increased risk of heart attack and stroke.
- Diagnosis of liver disease, since fibrinogen production can decrease in severe liver failure.
Interpretation of P-Fibrinogen test results
- High fibrinogen May indicate inflammation, infection, cardiovascular disease, cancer or chronic diseases. May also be elevated in pregnancy and smoking.
- Low fibrinogen May indicate liver disease, DIC (disseminated intravascular coagulation), genetic fibrinogen deficiency conditions or severe malnutrition.
Limitations and supplementary analyses
Fibrinogen is a non-specific biomarker and should always be interpreted in conjunction with other blood tests, such as CRP, D-dimer and complete coagulation work-up. If coagulation disorders are suspected, additional tests such as APTT and PK(INR) may be relevant.