: Fibrinogen Antigen and Functional Activity, Plasma

: What Is Fibrinogen?

: Fibrinogen is a protein produced by the liver that circulates in the bloodstream. When you are injured, fibrinogen is converted into fibrin, which forms the mesh-like structure of a blood clot. Both the quantity of fibrinogen and its functional quality matter for normal clotting.

: Why Is This Test Ordered?

: Your healthcare provider may order fibrinogen testing if you have unexplained bleeding or unusual blood clotting, if you have liver disease, or if you are being monitored during certain treatments. It may also be part of a broader evaluation of your blood's clotting ability.

: How the Test Is Performed

: This test requires a blood sample, usually drawn from a vein in your arm. The sample is collected in a tube containing an anticoagulant and sent to the laboratory, where fibrinogen antigen (the amount of protein present) and functional activity (how well it works) are assessed.

: What the Results Can Mean

: Fibrinogen levels that are lower than expected may suggest increased bleeding risk, liver dysfunction, or consumption of clotting factors. Higher-than-expected levels can occur with inflammation, infection, or certain other conditions. Your provider will interpret results in the context of your overall health and other tests.