For immunocompromised individuals, the Mantoux test is considered positive at which induration size?

For immunocompromised individuals, the Mantoux test is considered positive at which induration size?

• A. Induration greater than 3 mm
• B. Induration greater than or equal to 5 mm
• C. Induration greater than 10 mm
• D. Induration greater than 15 mm

Answer: (B)

The reading threshold for a Mantoux tuberculin skin test depends on immune status. In people who are immunocompromised, the immune response can be blunted, so a smaller induration is still clinically meaningful. Therefore, an induration of 5 millimeters or more is considered positive for them. This is lower than thresholds used for others, where 10 millimeters or 15 millimeters might be used depending on exposure risk. Note: measurement is the raised, palpable induration in millimeters measured 48–72 hours after injection, not just redness.

The reading threshold for a Mantoux tuberculin skin test depends on immune status. In people who are immunocompromised, the immune response can be blunted, so a smaller induration is still clinically meaningful. Therefore, an induration of 5 millimeters or more is considered positive for them. This is lower than thresholds used for others, where 10 millimeters or 15 millimeters might be used depending on exposure risk.

Note: measurement is the raised, palpable induration in millimeters measured 48–72 hours after injection, not just redness.