PPD皮肤试验

定义

The PPD皮肤试验 is a method used to diagnose silent (latent) 肺结核 结核病感染. PPD代表纯化蛋白衍生物.

选择的名字

Purified protein derivative standard; TB skin test; Tuberculin skin test; Mantoux test

如何执行测试

You will need two visits to your health care provider's office for this test.

At the first visit, the provider will clean an area of your skin, usually the inside of your forearm. You will get a small shot (injection) that contains PPD. The needle is gently placed under the top layer of skin, causing a bump (welt) to form. This bump usually goes away in a few hours as the material is absorbed.

48到72小时后, you must return to your provider's office (in some cases, 这可以虚拟完成). Your provider will check the area to see if you have had a strong reaction to the test.

如何准备考试

这次考试不需要特别的准备.

Tell your provider if you have ever had a positive PPD皮肤试验. If so, you should not have a repeat PPD test, except under unusual circumstances.

Tell your provider if you have a medical condition or if you take certain medicines, 比如类固醇, 哪些会影响你的免疫系统. These situations may lead to inaccurate test results.

Tell your provider if you have received the BCG vaccine and if so, when you received it. (This vaccine is only given outside of the United States).

考试的感觉如何

You will feel a brief sting as the needle is inserted just below the skin surface.

为什么要进行测试

This test is done to find out if you have ever come in contact with the bacteria that cause TB.

结核病是一种容易传播(传染)的疾病. 它最常影响肺部. The bacteria can remain inactive (dormant) in the lungs for many years. 这种情况被称为潜伏性结核病.

Most people in the United States who are infected with the bacteria do not have signs or symptoms of active TB.

如果你符合以下欧洲杯竞猜网站入口，你最有可能需要这个测试:

• 可能身边有肺结核患者
• 保健工作
• Have a weakened immune system, due to certain medicines or disease (such as cancer or HIV/AIDS)

正常的结果

A negative reaction usually means you have never been infected with the bacteria that cause TB.

带着负面反应, the skin where you received the PPD test is not swollen, 或者肿胀很小. This measurement is different for children, people with HIV, and other high-risk groups.

PPD皮肤试验并不是一个完美的筛选试验. A few people infected with the bacteria that cause TB may not have a reaction. Also, diseases or medicines that weaken the immune system may cause a false-negative result.

异常结果意味着什么

An abnormal (positive) result means you have been infected with the bacteria that cause TB. You may need treatment to lower the risk of the disease coming back (reactivation of the disease). A positive skin test does not mean that a person has active TB. More tests must be done to check whether there is active disease.

A small reaction (5 mm of firm swelling at the site) is considered to be positive in people:

• 谁患有艾滋病毒/艾滋病
• 谁接受过器官移植
• Who have a suppressed immune system or are taking steroid therapy (about 15 mg of prednisone per day for 1 month)
• Who have been in close contact with a person who has active TB
• Who have changes on a chest x-ray that look like past TB

Larger reactions (larger than or equal to 10 mm) are considered positive in:

• People with a known negative test in the past 2 years
• 糖尿病患者, 肾功能衰竭, or other conditions that increase their chance of getting active TB
• 卫生保健工作者
• 注射吸毒者
• Immigrants who have moved from a country with a high TB rate in the past 5 years
• 4岁以下儿童
• Infants, children, or adolescents who are exposed to high-risk adults
• Students and employees of certain group living settings, 比如监狱, 养老院, 无家可归者收容所

在没有已知结核病风险的人群中, 15 mm or more of firm swelling at the site indicates a positive reaction.

People who were born outside the United States who have had a vaccine called BCG may have a false-positive test result.

风险

There is a very small risk for severe redness and swelling of the arm in people who have had a previous positive PPD test and who have the test again. Generally, people who have had a positive test in the past should not be retested. This reaction can also occur in a few people who have not been tested before.

参考文献

菲茨杰拉德DW，斯特林TR，哈斯DW. 结核分枝杆菌. In: Bennett JE, Dolin R, Blaser MJ，编辑. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9日艾德. Philadelphia, PA: Elsevier; 2020:chap 249.

Rodino KG, Woods GL, Wengenack NL. 分枝杆菌. 见:McPherson RA, Pincus MR，编辑. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 59.