Fibrinogen

Formal name: Factor I

The Test Sample

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 factors. As the cascade nears completion, soluble fibrinogen (fibrinogen dissolved in fluid) is changed into insoluble fibrin threads. These threads cross-link to form a fibrin net and then stabilize at the injury site. The net adheres there, 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 area has healed.

How is the sample collected for testing?

A blood sample is collected by inserting a needle into a vein in the arm. As an alternative, particularly in paediatric care, the blood sample is collected by quickly pricking the fingertip with a lancet.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

If you don't know what a word or a medical term means, try the Mondofacto Online Medical Dictionary .