If the first of two TB tests is negative, when should the second test be administered?

When conducting a two-step TB testing procedure, the second test is typically administered 1 to 3 weeks after the first test, assuming the first test result is negative. This time frame is recommended to allow for a proper assessment of any potential delayed reaction to the tuberculin skin test, particularly in individuals who may have been recently infected with tuberculosis. By administering the second test within this window, healthcare providers can increase the accuracy of the screening process and ensure that any latent TB infection is not missed.

In clinical practice, it's important to follow this timeline to adhere to guidelines and ensure the best diagnostic outcomes for patients being evaluated for TB. The other time frames provided do not align with the established protocols for TB testing and could compromise the effectiveness of the testing process.