How to Interpret the Tuberculin Skin Test (TST) for Pulmonary Tuberculosis Screening

If you feel unwell and require antibiotic treatment, a skin test must be performed prior to initiating therapy. If the tuberculin skin test (TST) result is negative, antibiotics may be administered; however, if the result is positive, antibiotics should not be used. Thus, the TST result is critically important—failure to interpret it correctly may lead to serious consequences. So, how do you read the results of a tuberculosis (TB) screening skin test?

How to Interpret the Tuberculosis Screening Skin Test Result

The TB screening skin test result is assessed by observing the injection site and determining whether the reaction is negative or positive. After the intradermal injection, the patient should use a pen to draw a circle around the induration (raised area) at the injection site. The site must then be observed for 48–72 hours and compared with the original induration. Great care must be taken when drawing the circle—avoid rubbing it off or allowing water to wash it away, as this would render subsequent assessment of changes impossible. (Note: The sentence about drawing the circle is repeated in the original text.)

Please avoid spitting indiscriminately; instead, maintain good personal hygiene daily. Individuals particularly susceptible to tuberculosis often suffer from malnutrition and general physical weakness. Such individuals should take extra precautions. Wearing a mask in public places is strongly recommended to prevent cross-infection.

In daily life, cultivate healthy lifestyle and dietary habits. We hope this information has been helpful to you.