Analyte: Fibrinogen
Specimen Type: EDTA Plasma (Preferred), Citrate Plasma (Acceptable)
Optimum Volume: 0.5 mL
Reporting Units: mg/dL
Method: Immunoturbidimetric
2-8°C 2 days
-20°C 3 months
-70°C 3 years

Biological or Clinical Significance:

Fibrinogen is a soluble precursor of the insoluble fibrin, the major component of blood clots. It is a 340,000 Dalton glycoprotein composed of six subunits. When fibrinogen is activated by the proteolytic enzyme thrombin, four subunits are removed. The remaining units polymerize into fibrin strands, which form the basic structure of a blood clot. About 80% of fibrinogen is intravascular. It is synthesized in the liver at approximately 2-5 grams per day.

Fibrinogen is an acute phase protein and elevated levels of fibrinogen are associated with inflammation, trauma, surgery, and malignancy. Decreased levels are associated with congenital deficiencies or an increased use due to thrombosis or disseminated intravenous coagulation. The most common cause of low plasma fibrinogen is disseminated intravascular coagulation (DIC), a condition in which blood clots form throughout the microvascular system.

Principle of Test Method:

The Fibrinogen assay is an automated immunoturbidimetric method.