Test Details & Preparation

The factor VII assay is a blood test to measure the activity of factor VII - one of the substances needed for blood clotting (coagulation).

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The area is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

Your healthcare provider may ask you to stop taking certain medications for a factor VII assay test. This test is used to find the cause of excessive bleeding (decreased blood clotting).

The normal value is 50 - 200% of the laboratory control or reference value. Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Decreased factor VII activity may be related to congenital deficiency of factor VII disseminated intravascular coagulation (DIC) fat malabsorption liver disease (such as cirrhosis) taking Warfarin and vitamin K deficiency.