What does positive Mantoux look like?

A positive Mantoux Test, or tuberculin skin test (TST), is characterized by the presence of induration (raised, firm bump) at the test site. The appearance of the induration can vary depending on factors such as the individual's skin type, the volume of the purified protein derivative (PPD) injected, and the person's immune response. The induration is typically measured in millimeters (mm) using a ruler or calipers. A positive result indicates exposure to the tuberculosis (TB) bacteria and the development of a delayed-type hypersensitivity response. The size of the induration determines the interpretation of the test results. The induration is assessed within a specific time frame (usually 48 to 72 hours after the test administration) by healthcare professionals trained in TB management. It is important to consult with healthcare professionals familiar with the current guidelines and recommendations to accurately interpret the test results and determine the appropriate next steps based on the individual's specific circumstances.