Regarding Mantoux testing in TB management, which statement is true?

Regarding Mantoux testing in TB management, which statement is true?

• A. Mantoux will remain positive forever
• B. Mantoux test becomes negative after treatment
• C. Mantoux test is not useful at all
• D. Mantoux test can predict contagiousness

Answer: (A)

Mantoux testing reflects immune memory to TB antigens, not current disease activity. After TB exposure or Bacille Calmette-Guérin vaccination, the body’s memory T cells respond to the purified protein derivative, producing a skin reaction that tends to persist for many years, often lifelong. Because of that enduring immunologic memory, the idea that the Mantoux test will remain positive forever captures why a positive result is typically considered lifelong in practice. This test doesn’t indicate how contagious someone is—contagiousness depends on active, untreated disease with transmissible bacteria, not on past sensitization. It also isn’t reliably negative after treatment; treatment can clear infection, but the immune memory driving the skin test response can remain, so the test may stay positive. While the Mantoux test has limitations, such as false positives from prior BCG vaccination or non-tuberculous mycobacteria, it remains useful for identifying latent TB infection and guiding further evaluation and preventive therapy.

Mantoux testing reflects immune memory to TB antigens, not current disease activity. After TB exposure or Bacille Calmette-Guérin vaccination, the body’s memory T cells respond to the purified protein derivative, producing a skin reaction that tends to persist for many years, often lifelong. Because of that enduring immunologic memory, the idea that the Mantoux test will remain positive forever captures why a positive result is typically considered lifelong in practice. This test doesn’t indicate how contagious someone is—contagiousness depends on active, untreated disease with transmissible bacteria, not on past sensitization. It also isn’t reliably negative after treatment; treatment can clear infection, but the immune memory driving the skin test response can remain, so the test may stay positive. While the Mantoux test has limitations, such as false positives from prior BCG vaccination or non-tuberculous mycobacteria, it remains useful for identifying latent TB infection and guiding further evaluation and preventive therapy.