How to do BCG skin test

Newborn babies have very poor resistance and are easily attacked by some diseases. This is the main reason for injecting various vaccines. The KS vaccine is injected to prevent tuberculosis. A skin test is required before the injection. This is a very important test to ensure that the child will not have exclusion symptoms for the KS vaccine. So, how to do the BCG skin test? Let’s take a look at the specific method of the BCG skin test.

The reaction of the BCG skin test is an important basis for BCG vaccination, so it should be closely observed. The reaction is usually detected within 48-96 hours. The reaction of the BCG skin test is generally the appearance of local nodules. The main method of testing is to observe the horizontal and vertical diameters of the nodules. In addition to nodules, other possible reactions include blisters, necrosis or lymphadenitis. These are possible reactions after the BCG skin test, and the doctor will draw conclusions based on these reactions.

The results of the BCG skin test mainly depend on whether there is a nodule and the size of the nodule. If there is only a pinhole-sized mark at the site of PPD injection but no nodule, it is a negative reaction, indicating that the BCG vaccination has no effect. Further examination is needed to determine whether it is related to the baby's own immune function deficiency or the technical operation of the BCG vaccination process. If redness and swelling appear at the site and there is a nodule with a diameter of about 5-10 mm, it is a positive reaction, which means that the BCG vaccination is successful and resistance to tuberculosis has been developed in the body. Another situation is that the diameter of the nodule exceeds 20 mm, or there is redness and swelling, blisters and necrosis on the nodule, and it is accompanied by lymphatic vessels. These are all strong positive reactions and you should go to the hospital for further examination.