Fibrinogen

Share this page:
Formal name: Factor I

At a Glance

Why Get Tested?

To determine whether your fibrinogen level is adequate to allow normal blood clotting, to help diagnose disseminated intravascular coagulation (DIC), to help determine whether you have an inherited fibrinogen deficiency or abnormality. Sometimes as a non-specific marker of inflammation in the blood. Very occasionally to help evaluate your risk of developing cardiovascular disease

When to Get Tested?

When you have unexplained or prolonged bleeding, an abnormal Prothrombin Time (PT) or activated Partial Thromboplastin Time (aPTT) test, or have a relative with a hereditary fibrinogen deficiency or abnormality. To evaluate whether certain abnormalities in a Full Blood Count are due to inflammation or are self-generated. When your doctor wants additional information to help evaluate your risk of developing heart disease

Sample Required?

A blood sample taken from a vein in your arm, or sometimes, via a finger prick (mainly performed in children)

Test Preparation Needed?

None

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 stabilise 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.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

Ask a Laboratory Scientist

Article Sources

« Return to Related Pages

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.