Reading for Mantoux test is taken between:

IGNOU PB Bsc Entrance-2022

Medical & Surgical Nursing

Easy

Appeared in: IGNOU PB Bsc Entrance-2022

Explanation

The Mantoux test reading is optimally performed between 48 to 72 hours after the PPD solution is injected.
This specific timeframe is because the test relies on a Type IV delayed-type hypersensitivity reaction, an immune response that takes 2 to 3 days to reach its maximum presentation.
Reading the test within this window ensures the most accurate measurement of the body's cell-mediated immune response to the tuberculin antigens.
An earlier or later reading can lead to misinterpretation of the results.

Option A: Reading the test before 48 hours is too early. The delayed hypersensitivity reaction will not have fully developed, which could lead to a false-negative result, missing a potential TB infection.
Option B: This period is far too short for a cell-mediated immune response (Type IV) to become visible. The immune cells need more time to migrate to the site and mount a response.
Option D: This timeframe is associated with immediate (Type I) hypersensitivity reactions, such as those seen in allergy skin testing, not the delayed reaction used to screen for TB.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Timing for reading the Mantoux tuberculin skin test (TST) as background academic context rather than a clinical decision trigger.
Accurate timing in reading the Mantoux test is a critical nursing responsibility to ensure correct screening for tuberculosis, preventing false negatives that could delay treatment and allow for disease transmission.
Patient education is paramount. The nurse must clearly instruct the patient on the importance of returning for the reading within the 48-72 hour window and advise them not to scratch or cover the site, as this can interfere with the result.
What if? If a patient returns for a reading after 72 hours (e.g., at 96 hours), the result is considered unreliable and potentially smaller than its peak. The test should be documented as 'not read' and a repeat test should be scheduled, often on the other arm.

How to Approach the Question

First, identify the core subject of the question, which is the 'Mantoux test' and the 'reading' time.
Recognize that this is a factual recall question about a specific parameter of a common diagnostic procedure.
Recall the underlying immunological principle of the test: it is a delayed-type (Type IV) hypersensitivity reaction.
Connect this principle to the timing. Delayed reactions, by definition, take time to develop, typically peaking in 2-3 days.
Convert 2-3 days into hours (48-72 hours) and select the option that matches this timeframe.
Eliminate options that represent timeframes that are too short for a delayed reaction to occur.

Concept Tested & Keywords

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