Coagulation factors are proteins in your blood. They help form blood clots to stop bleeding when you have an injury. These proteins are also called clotting factors. You have several different types of clotting factors that are all important for making blood clots.

Coagulation factor tests are blood tests that check one or more of your clotting factors to see if you:

• Have too much or too little of a clotting factor
• Are missing a clotting factor
• Have a clotting factor that isn’t working properly

Your liver makes most of your clotting factors. But normally, clotting factors are turned off, so you don’t form abnormal blood clots. When you have an injury that causes bleeding, blood cells called platelets begin to make a soft blood clot to stop the bleeding.

The platelets release molecules into your blood that begin to turn on the clotting factors. The clotting factors work together in a chain reaction to form a harder blood clot that will stay firmly in place.

Problems with any one of your clotting factors may mean that:

• Your blood clots too easily, even without an injury. This condition may lead to clots that block your blood flow and cause serious conditions, such as heart attack, stroke, or clots in the lungs.
• Your blood doesn’t clot enough after an injury or surgery. If this happens, you have a bleeding disorder. Bleeding disorders can lead to serious blood loss after an injury.

Clotting factors have names, such as fibrinogen and prothrombin. Each clotting factor also has a Roman numeral name, such as “clotting factor II.”

Other names: blood clotting factors, factor assays, factor assay by number (Factor I, Factor II, Factor VIII, etc.) or by name (fibrinogen, prothrombin, hemophilia A, hemophilia B, etc.), coagulation panel

What is it used for?

A coagulation factor test is used to find out if you have a problem with any of your clotting factors that may cause too little or too much blood clotting.

Coagulation factor tests are also used to monitor people who have a known problem with clotting factors or who take medicine called blood thinners to lower the risk of blood clots.

You may have tests for one or more factors at a time.