How to see the results of pulmonary tuberculosis skin test

After 48 ~ 72 hours of tuberculin test, check the reaction. If there is a big red dot or a little redness at the injection site, and the induration diameter is less than 0.5 cm, it is a negative reaction. If the diameter of the hard segment at the injection site is more than 0.5 cm, but less than 1.5 cm, it is a positive reaction. If the injection site reacts strongly or the diameter of the hard segment exceeds 1.5 cm, it is a strong positive reaction. Positive reaction means that the body has allergic reaction to mycobacterium tuberculosis, and it has been infected with tuberculosis in the past, but it does not mean that it is sick, because people who have been vaccinated with BCG are also positive. A strong positive reaction indicates that there may be active infection, and it is necessary to further check whether there is tuberculosis. Negative reaction shows that there is no tuberculosis infection.