补充

定义

补充 is a blood test that measures the activity of certain proteins in the liquid portion of your blood.

补体系统 is a group of nearly 60 proteins that are in blood plasma or on the surface of some cells. The proteins work with your immune system 和 play a role to protect the body from infections, 和 to remove dead cells 和 foreign material. Rarely, people may inherit deficiency of some complement proteins. These people are prone to certain infections or 自身免疫性疾病s.

There are nine major complement proteins. They are labeled C1 through C9. This article describes the test that measures total complement activity.

选择的名字

补充 assay; 补充 proteins

如何执行测试

需要血液样本. This is most often taken through a vein. 这个过程称为a 静脉穿刺.

How to Prepare for the Test

There is no special preparation.

考试的感觉如何

When the needle is inserted to draw blood, some people feel slight pain. Others may feel only a prick or sting. Afterward, there may be some throbbing.

为什么要进行测试

Total complement activity (CH50, CH100) looks at the overall activity of the complement system. In most cases, other tests that are more specific for the suspected disease are done first. C3 和 C4 are the complement components measured most often.

A complement test may be used to monitor people with an 自身免疫性疾病. It is also used to see if treatment for their condition is working. For example, people with active 红斑狼疮 may have lower-than-normal levels of the complement proteins C3 和 C4.

补充 activity varies throughout the body. For example, in people with 类风湿性关节炎, complement activity in the blood may be normal or higher-than-normal, but much lower-than-normal in the joint fluid.

People with some bacterial blood infections 和 冲击 often have very low C3 和 components of what's known as the alternative pathway. C3 is often also low in fungal infections 和 some parasitic infections, such as 疟疾.

正常的结果

The normal results for this test are:

• Total blood complement level: 41 to 90 hemolytic units
• C1等级:14.9 to 22.1 mg / dL
• C3水平:88到201毫克/分升
• C4水平:15到45毫克/分升

Note: mg/dL = milligrams per deciliter.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your health care provider 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.

异常结果意味着什么

Increased complement activity may be seen in:

• 癌症
• 某些感染
• 溃疡性结肠炎

Decreased complement activity may be seen in:

• 肝硬化
• 肾小球肾炎
• 遗传性血管性水肿
• 肝炎
• 肾移植 拒绝
• 狼疮肾炎
• 营养不良
• Systemic 红斑狼疮
• Rare inherited complement deficiencies

风险

风险 associated with having blood drawn are slight, but may include:

• 大出血
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

注意事项

The "complement cascade" is a series of reactions that take place in the blood. The cascade activates the complement proteins. The result is an attack unit that creates holes in the membrane of bacteria, killing them.

参考文献

毕恩KV，马西D，古普塔G. Mediators of inflammation: complement. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis 和 Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 47.

Ram年代. 补充 和 deficiencies. In: Bennett JE, Dolin R, Blaser MJ, eds. M和ell, Douglas, 和 Bennett's Principles 和 Practice of Infectious Diseases. 9日艾德. Philadelphia, PA: Elsevier; 2020:chap 9.

Sullivan KE, Grumach AS. 补体系统. In: Burks AW, Holgate ST, O'Hehir RE, Broide DH, et al. eds. Middleton's Allergy: Principles 和 Practice. 9日艾德. Philadelphia, PA: Elsevier; 2020:chap 8.