It’s the beginning of school again. Students, please quickly get ready for school! Have you taken the entrance physical examination required by the school? Have you ever paid attention to a special test in the physical examination - tuberculin test (PPD) ? Many students and parents have questions, why do we need this examination? What does this check do?
Why do new students entering the school need to be screened for tuberculosis?
Currently Tuberculosis is still one of the major infectious diseases that endangers the health of the people in our country. Tuberculosis is mainly transmitted through the respiratory tract. In densely populated schools, if there is a source of infection and it is not dealt with in time, it can easily cause spread and epidemic, which will cause great harm to people. The school's teaching has a great impact and causes great harm to the physical and mental health of patients, teachers and students. To this end, according to relevant regulations, tuberculosis examination items are required as part of the physical examination for new students and routine physical examinations for faculty and staff. Qualified physical examination institutions will conduct physical examinations for school teachers and students, and the results of the physical examination will be included in the health files of students and faculty.
What is PPD test ?
PPD (tuberculin test) is a skin test based on the principle of type IV allergy and is a commonly used reference indicator for diagnosing tuberculosis infection. Any body that has been infected with Mycobacterium tuberculosis will produce corresponding -sensitized lymphocytes , which have the ability to recognize Mycobacterium tuberculosis. When encountering a small amount of Mycobacterium tuberculosis or tuberculin again, the sensitized T lymphocytes are stimulated again by the same antigen and release a variety of soluble lymphokines, leading to an increase in vascular permeability. macrophages locally Agglomeration leads to infiltration. Within about 48 to 96 hours, a positive reaction of red, swollen and hard nodules will appear locally. If the subject has not been infected with Mycobacterium tuberculosis, no allergic reaction will occur at the injection site.
What do you think of the results of the tuberculin test?
uses skin induration as the criterion for judging local skin reactions:
The diameter of the induration is less than or equal to 5 mm, which is negative,
5-9 mm, which is generally positive,
10-19 mm, which is moderately positive,
which is greater than 20 mm or less than 20 mm, but there is Blisters, necrosis, lymphangitis or double circle reaction are strongly positive.
Does a positive tuberculin test mean you have tuberculosis?
PPD test is a preliminary screening test for tuberculosis, but it cannot be used as a confirmatory test. A positive tuberculin test has the following possibilities:
. Being infected with tuberculosis: At this time, it is necessary to know the location and scope of the lesion as soon as possible, and start anti-tuberculosis treatment as soon as possible;
2. There is a history of tuberculosis infection: that is, positive only means that you have been infected with tuberculosis. , but there is no active infection with tuberculosis bacteria, and anti-tuberculosis treatment is not needed for this situation;
3. Have a history of vaccination: I have been injected with BCG vaccine, which is the vaccine to prevent tuberculosis. The vaccine causes the body to produce an immune response. It shows a positive result in the tuberculin test and does not require additional medication;
so the tuberculin test A positive result does not necessarily mean that bacteria are actively replicating. Further examination is required to determine whether formal anti-tuberculosis treatment needs to be started.
What are the precautions for doing PPD test?
. Patients with allergies should inform the nurse in advance.
2. After the injection, slightly raise the upper limbs, do not squeeze the injected skin, and leave after a short rest without any discomfort.
3. Do not scratch or rub the injection site with your hands to avoid infection and inflammation. Do not apply any medicine, toilet water, soap, etc. to avoid affecting the judgment of the results.
4. Do not wear watches, jewelry or perform other treatments at the injection site before the results are available.
5. Get the results (this item is very important): You must come in person to get the report form within 48-96 hours after the injection (the test results are in the hands of the person who injected them), family members cannot replace you (the report form will not be issued in advance or postponed) , you can also pick it up at noon).
Please bring the "Tuberculin Risk Information" to get the test report
After reading the above introduction, do parents and students have a certain understanding of the PPD test? Let's get ready for the start of school together! (Text / Zeng Feifei, Wan Yan)
Tuberculin test (PPD) reminder
Time: Monday to Sunday 8:00-17:00
Location: No. 346 Dieshan Road, Nanchang City Jiangxi Provincial Chest Hospital Outpatient Department
