因子IX测定

定义

The factor IX assay is a blood test that measures the activity of factor IX. This is one of the proteins in the body that helps the blood clot.

选择的名字

Christmas factor assay; Serum factor IX; Hemophilic factor B; Plasma thromboplastin component; PTC

How the Test is Performed

A 血液样本 是必要的.

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

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 血友病B. The test may also be done to see how well treatment for 血友病B 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 provider about the meaning of your specific test results.

The examples above show the common measurements for results for these tests.

What Abnormal Results Mean

Decreased factor IX activity may be related to:

• 血友病B (a bleeding disorder caused by a lack of blood clotting factor IX)
• Disorder in which the proteins that control blood clotting become overactive (disseminated intravascular coagulation)
• 脂肪 吸收不良 (not absorbing enough fat from your diet)
• 肝脏疾病 (如 肝硬化)
• 维生素K 缺乏
• Taking blood thinners

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 excessive bleeding is slightly more than for people without 出血的问题.

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.

派M，莫法特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.

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.