因子V试验

定义

The factor V assay is a blood test to measure the activity of factor V. This is one of the proteins in the body that helps the blood clot.

Alternative Names

Labile factor; Proaccelerin; Ac-globulin

How the Test is Performed

A 血液样本 是必要的.

How to Prepare for the Test

No special preparation 是必要的.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.

Why the Test is Performed

This test is used to find the cause of too much bleeding (decreased blood clotting). This decreased clotting may be caused by an abnormally low level of factor V.

正常的结果

The value is normally 50% to 200% of the laboratory control or reference value.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

Decreased factor V activity may be related to:

• Factor V deficiency (a bleeding disorder that affects the ability of blood to clot)
• Disorder in which the proteins that control blood clotting become overactive (disseminated intravascular coagulation)
• 肝脏疾病 (如 肝硬化)
• Abnormal breakdown of blood clots (secondary fibrinolysis)

风险

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Obtaining a 血液样本 from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• 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.

参考文献

Pai M, Moffat KA. Laboratory evaluation of hemostatic and thrombotic disorders. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8日艾德. Philadelphia, PA: Elsevier; 2023:chap 127.

Sarode R, Kessler CM. Coagulation and fibrinolysis. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 40.