Mantoux (tuberculin) testing: In which situations are false-negative Mantoux results most likely to occur?

Introduction / Context:
The Mantoux test depends on intact cell-mediated immunity. Conditions that blunt T-cell responsiveness can lead to false-negative results even when Mycobacterium tuberculosis infection is present. Recognizing these scenarios is crucial for clinical interpretation and public health decisions.

Given Data / Assumptions:

• The question asks about causes of false negativity, not true negativity.
• Examples include early infection, advanced disease, and malnutrition.
• Other immunosuppressive states act similarly (e.g., HIV, corticosteroids).

Concept / Approach:
False negatives arise when delayed-type hypersensitivity is not yet developed (window period) or is impaired by anergy. Early TB (prior to sensitization) may not elicit an induration. In advanced, disseminated TB, immune exhaustion or anergy can reduce responsiveness. Severe protein-calorie malnutrition impairs T-cell function, decreasing the reaction. Therefore, a negative test does not exclude TB in these settings.

Step-by-Step Solution:
List conditions that suppress DTH responses: early infection, anergy, malnutrition. Relate each to reduced induration despite infection. Recognize all choices describe recognized false-negative scenarios. Choose “All of these.”

Verification / Alternative check:
Clinical practice uses interferon-gamma release assays or repeats testing after the window period if suspicion remains high; this supports the understanding that false negatives occur in these states.

Why Other Options Are Wrong:

• Each single option is correct but incomplete alone.
• None of these: Incorrect because all listed conditions can cause false negatives.

Common Pitfalls:
Over-relying on a single negative Mantoux in high-risk or symptomatic patients; ignoring malnutrition or immune suppression in interpretation.

Final Answer:
All of these.