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Factor X assay


Definition:

The factor X assay is a blood test to measure the activity of factor X .This is one of the substances involved in blood clotting (coagulation).

How the Test is Performed:

A sample of blood will be taken from a vein.

How to Prepare for the Test:

You may need to stop taking some medicines before this test. Your health care provider will tell you which ones

How the Test will Feel:

You may feel slight pain or a sting when the needle is inserted to draw blood. You may feel some throbbing afterward.

Why the Test is Performed:

This test may be used to find the cause of excessive bleeding (decreased blood clotting).

Normal Results:

A 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.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean:

Decreased factor X activity may be related to:

Risks:

Veins and arteries vary in size so it may be harder to take a blood sample from one person than another.

Other slight risks from having blood drawn are may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

This test is most often performed on people who have bleeding problems. The risk of excessive bleeding is slightly greater than for people without bleeding problems.

Considerations:

When you bleed, the body starts a series of activities that help the blood clot. This is called the coagulation cascade. The process involves special proteins called coagulation factors (factor X is a coagulation factor).

Each factor's reaction triggers the next reaction. The final product of the coagulation cascade is the blood clot. Blood clots may not form normally if any one of the clotting factors is abnormally low.

References:

Gailani D, Neff AT. Rare coagulation factor deficiencies. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Saunders Elsevier; 2012:chap 139.

Ragni MV. Coagulation factor deficiencies. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 177.


Review Date: 3/3/2013
Reviewed By: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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