What is being tested?Fibrinogen is a coagulation factor, a
protein that is essential for blood clot formation. It is produced by the liver and released into the circulation as needed along with over 20 other clotting factors. Normally, when a body tissue or blood vessel wall is injured, a process called the
coagulation cascade activates these clotting factors one after the other. As the cascade nears completion, soluble fibrinogen (fibrinogen dissolved in fluid) is changed into insoluble fibrin threads. These threads crosslink together to form a fibrin net that stabilizes at the injury site. The fibrin net adheres to the site of injury along with aggregated cell fragments called platelets to form a stable blood clot. This barrier prevents additional blood loss and remains in place until the injured area has healed.
Fibrinogen is one of several blood factors that are called acute phase reactants. Blood levels of fibrinogen along with other acute phase reactants rise sharply with conditions causing acute tissue inflammation or damage.
Fibrinogen testing measures the amount of soluble Factor I (fibrinogen dissolved in the blood), before it has been turned into insoluble fibrin and been crosslinked into a fibrin net.
