Formal Name
Factor I
This article was last reviewed on
This article waslast modified on 7 June 2023.
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 fibrinogen can be a non-specific marker of inflammation in the blood, and very occasionally it helps evaluate your risk of developing cardiovascular disease. High fibrinogen levels may rarely be related to an increased risk of venous thrombosis (blood clots).

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

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

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...

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