因子8测定

定义

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

选择的名字

Plasma factor VIII antigen; Antihemophilia factor; AHF

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). Or, it may be ordered if a family member is known to have A型血友病. The test may also be done to see how well treatment for A型血友病 is working.

正常的结果

A normal value is 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 VIII activity may be due to:

• Hemophilia A (a bleeding disorder caused by a lack of blood clotting factor VIII)
• Disorder in which the proteins that control blood clotting become overactive disseminated intravascular coagulation (DIC)
• Presence of a Factor VIII inhibitor (antibody)
• Von Willebrand disease (another type of bleeding disorder)

Increased activity may be due to:

• 老年
• 糖尿病
• 肝脏疾病
• 炎症
• 怀孕
• 肥胖

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 done on people who have 出血的问题. The risk of too much bleeding is slightly greater for people with 出血的问题 than others.

参考文献

Carcao M, Gomez K, Davide M, Pierce GF. Hemophilia A and B. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8日艾德. Philadelphia, PA: Elsevier; 2023:chap 134.

情景不禁啜泣MV. Hemorrhagic disorders: coagulation factor deficiencies. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 165.

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.