Tuberculin test (OT, PPD)

The tuberculin test is a test in which a tuberculosis skin test is performed to determine whether the body has an allergic reaction to Mycobacterium tuberculosis. The tuberculin used for the test is a protein component of Mycobacterium tuberculosis. There are two kinds of crude products which are concentrated after the culture of Mycobacterium tuberculosis, which is called old tuberculin (OT), and the product is used for skin test. The OT test is called; the other is a purified preparation of Mycobacterium tuberculosis culture called pure protein derivative (PPD). For the tuberculin test, OT or PPD is injected into the forearm skin, and the red and indurated induration is more than 5 mm positive for 48 to 72 hours, otherwise it is negative. Basic Information Specialist classification: infectious disease inspection and inspection classification: other inspection Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Normal value: no Above normal: negative: normal. Positive: Prompt for tuberculosis infection. Tips: When checking the reaction, if there are local blisters and ulcers, it should be kept dry to prevent infection and reduce forearm activity. Normal value The normal person is weakly positive, that is, the induration diameter is 5 to 9 mm. Clinical significance 0.1ml 1:2000 OT dilution (5TU), intradermal injection of the left forearm, skin induration diameter measured 48 ~ 72h, such as a diameter of 5 ~ 9mm is a weak positive reaction (prompting mycobacterial infection, also including SARS Mycobacterial infection); 10 ~ 19mm is a positive reaction; more than 20mm or local skin blisters and necrosis is a strong positive reaction, suggesting that there may be active infection. PPR-TR23, 2TU, which is uniformly supplied by the International Health Organization, is weakly positive with an induration diameter greater than 6 mm, and tuberculosis infection is indicated above 10 mm. However, if a high-dilution (1TU, ie 1:10000OT) is used as a strong skin test, it is often suggested that there is an active source in the body. A positive tuberculosis test indicates that the subject has been infected with tubercle bacilli and has immunity against tuberculosis, and does not necessarily have tuberculosis. The person who has been vaccinated with BCG is also positive. In addition to the unsuccessful vaccination of BCG or BCG, the negative results of the serotonin test were also found in the following cases: 1 In the early stage of Mycobacterium tuberculosis infection, the body has not established an anti-tuberculosis immunity tuberculosis infection 4 to 8 weeks after the allergic reaction can be fully established, in this allergic phase pre-terminus test can be negative. 2 severe tuberculosis such as tuberculous meningitis, systemic miliary tuberculosis, low cellular immune function, and various critically ill patients do not respond to the nodules, or only weak positive, which is due to the temporary suppression of human immunity and allergic reactions As a result, when the condition improves, it will turn into a positive reaction. 3 The use of immunosuppressive agents such as glucocorticoids, malnutrition and patients with measles, whooping cough, etc., can also be temporarily negative. 4 Lymphocyte immune system defects (such as lymphoma, leukemia, sarcoidosis, AIDS, etc.) patients and the elderly are often negative. Precautions 1. The knot should be refrigerated (2 ~ 8 ° C), protected from light, can not be placed directly on the ice, not mixed with other drugs. 2. The ampoule is used up within 1 hour after opening. 3. The test should be carried out indoors to avoid exposure to sunlight. 4. The lignin test uses a disposable syringe. 5. Do a good job of propaganda and avoid tension. 6. When investigating the population, the fever and obvious debilitating are not applied. 7. Symptoms such as syncope, snoring reaction, allergic reaction and anaphylactic shock, injection of local ulcer, infection and necrosis at the time of injection or injection should be given symptomatic treatment in time. 8. When detecting the reaction, if there is local blisters or ulcers, it should be kept dry to prevent infection and reduce forearm activity. 9. The batch number should be recorded. Inspection process 1. Check the name, dosage and expiration date before the test. If there is sedimentation, damage to the ampoule and expired, it should not be used. 2. In the center of the left forearm (or back) side without scars or lesions, disinfect the skin with ethanol. 3. Apply 1ml disposable syringe, the scale and the pinhole slope are consistently upward, and penetrate into the skin parallel to the skin. Slowly and accurately inject 0.1ml (including 5UPPD), and the white bulge with a diameter of about 6~10mm, don't try to figure it out. Will resolve on its own. 4.72h (48 ~ 96h) check the reaction, measure the transverse diameter and vertical diameter of the local induration reaction, or only measure the transverse diameter, record the actual size of the measurement, such as blisters, papules, lymphangitis, etc., should also be Record the size after the date. Not suitable for the crowd There are no taboos. Adverse reactions and risks There are no related complications and hazards.