In HIV positive patient Mantoux tuberculin test is positive when the scar is more than-

Combined AIIMS - 2020 (Jodhpur, Bhopal, Patna, Raipur)

Medical & Surgical Nursing

Easy

Appeared in: Combined AIIMS - 2020 (Jodhpur, Bhopal, Patna, Raipur)

Explanation

In HIV-positive individuals, the immune system is suppressed, which can lead to a weaker reaction to the tuberculin antigen.
To account for this reduced immune response (anergy), the threshold for a positive test is lowered to 5 mm of induration.
This lower cutoff increases the sensitivity of the test, ensuring that true TB infections are not missed in this high-risk population.
This criterion also applies to other severely immunosuppressed groups, such as organ transplant recipients or those on long-term steroid therapy.

Option B: 7mm is not a standard cutoff for interpreting a Mantoux test. The standard thresholds are 5 mm, 10 mm, and 15 mm.
Option C: An 11mm induration would be considered positive, but the minimum threshold for an HIV-positive patient is 5mm. Waiting for an 11mm reaction could lead to a missed diagnosis. An induration of 10mm or more is the cutoff for individuals with other risk factors, not specifically HIV.
Option D: A 15mm induration is the threshold for a positive test in individuals with no known risk factors for TB. Applying this standard to an HIV-positive patient would result in a high rate of false-negative results.

Clinical Relevance

Nursing practice connection: Use the key finding related to Interpretation of Mantoux Tuberculin Skin Test (TST) in Immunocompromised Patients to guide bedside assessment, documentation, and the next nursing action.
Nurses are responsible for correctly administering the TST, reading the result at the appropriate time (48-72 hours), and accurately measuring the induration.
A positive TST in an HIV patient is a significant finding that requires prompt reporting and follow-up with further diagnostic tests like a chest X-ray and sputum analysis to rule out active TB disease.
Patient education is crucial. The nurse must instruct the patient to not scratch or cover the site and to return for the reading within the 48-72 hour window.

How to Approach the Question

First, identify the key elements of the question: the test being performed (Mantoux tuberculin test) and the specific patient population (HIV positive).
Recognize that the patient's HIV status is a critical modifier. Standard diagnostic criteria are often different for immunocompromised individuals.
Recall the specific guidelines for interpreting the Mantoux test based on risk factors.
Remember that for the most high-risk and immunocompromised groups, including HIV-positive persons, the smallest induration size (≥5 mm) is used as the cutoff for a positive result.
Evaluate the options based on this specific criterion, eliminating the higher thresholds that apply to lower-risk groups.

Concept Tested & Keywords

Concept Tested: Interpretation of Mantoux Tuberculin Skin Test (TST) in Immunocompromised Patients
Stem keywords: HIV positive, Mantoux tuberculin test, positive
Lead-in keywords: more than
Clinical cues: The patient's HIV-positive status is the critical factor that modifies the standard interpretation of the test.

QsAQ3rqSbORkZxLdJRLWOH

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 25-27

E6 Medicine Harrison 22e Part 1 p. 1442-1444