What measurement of induration is considered positive for HIV-infected individuals?

In the context of tuberculin skin testing (TST), a positive result indicates that a person has been exposed to the bacteria that cause tuberculosis. For HIV-infected individuals, the threshold for a positive result is set at greater than or equal to 5mm of induration. This lower cutoff reflects their increased risk of developing active tuberculosis disease due to their immunocompromised status.

In healthy individuals or those with no risk factors, the induration cut-off can be higher, indicating that the test is calibrated to account for varying degrees of immune response. For HIV-positive patients, even a minimal response is clinically significant; therefore, a induration of 5mm or more is sufficient to prompt further evaluation and management regarding tuberculosis exposure. Understanding this threshold is crucial for healthcare providers when interpreting results and ensuring appropriate care for HIV-infected individuals.