Fibrinogen

The function of fibrinogen

Together with platelets and other clotting factors, fibrinogen ensures that your blood clots properly. This is essential to prevent excessive blood loss when an injury damages a blood vessel.

When bleeding occurs, your body starts a chain reaction involving various clotting factors. Ultimately, fibrinogen is converted into fibrin. At the site of the injury, fibrin forms long strands that trap platelets to create a clot. Sometimes, blood clots inside a blood vessel without an external wound; this is known as thrombosis.

Normal fibrinogen levels

The blood of a healthy adult contains between 2.0 and 4.0 g/L of fibrinogen, which is sufficient for normal blood clotting. If fibrinogen levels are too low, blood may not clot effectively.

It is important to identify the cause of abnormally low or high fibrinogen levels. A blood test can determine your fibrinogen level and help investigate any underlying cause. Sanquin does not measure fibrinogen levels in blood donors.

What happens if fibrinogen levels are too low?

If fibrinogen levels are too low, your blood does not clot properly or clots too slowly, which can lead to increased blood loss.

Low fibrinogen levels can be a chronic condition, for example, if you have a rare hereditary condition such as afibrinogenemia or hypofibrinogenemia. In most cases, however, an abnormally low level is caused by an underlying issue, such as liver disease or severe bleeding. Additionally, fibrinogen levels can drop due to certain medications, such as blood thinners.

What does it mean if your fibrinogen level is too high?

A fibrinogen level above 4.0 g/L is considered high. While this usually does not cause symptoms, it can indicate inflammation or another underlying condition.

Fibrinogen is an "acute-phase protein," meaning its concentration rises quickly during inflammation. Surgery, a heart attack, an injury, or cancer can also cause fibrinogen levels to elevate. Furthermore, fibrinogen levels naturally increase during pregnancy. Once the underlying cause is resolved, levels typically return to normal.

Fibrinogen in plasma

Like other clotting factors, fibrinogen is found in blood plasma. This is why plasma is administered to patients experiencing severe blood loss, providing them with the necessary clotting factors to help their blood clot more effectively.

You can also choose to donate plasma. Did you know that your body recovers faster from a plasma donation than from a whole blood donation? During plasma donation, we collect only the plasma and return your blood cells to you.

This allows your body to recover quickly, enabling you to donate more frequently, up to 26 times a year! However, we are grateful for every single donation. Want to know more about plasma donation? Take a look at our plasma page.