Which one of the following is a test for Diphtheria?

Appeared in: RRB Staff Nurse Kolkata-2015

Explanation

The Schick test is a skin test used to determine an individual's susceptibility to diphtheria.
It involves the intradermal injection of a diluted diphtheria toxin.
A local inflammatory reaction (a positive result) indicates that the person lacks sufficient neutralizing antibodies and is therefore susceptible to the disease.
A negative result (no reaction) indicates the presence of protective antibodies, signifying immunity.

Option A: The Mantoux test, or tuberculin skin test (TST), is used to screen for exposure to Mycobacterium tuberculosis, the bacterium that causes tuberculosis.
Option C: The WIDAL test is a serological test used to help diagnose typhoid fever (enteric fever), which is caused by Salmonella Typhi.
Option D: The VDRL (Venereal Disease Research Laboratory) test is a screening test for syphilis, a sexually transmitted infection caused by the spirochete Treponema pallidum.

Visual 1: Diagram: A visual guide illustrating the procedure for the Schick test, showing the injection site on the forearm and comparing the appearance of a positive (red, swollen) and negative (no reaction) result.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic and susceptibility tests for infectious diseases as background academic context rather than a clinical decision trigger.
The Schick test is now largely of historical interest due to widespread childhood immunization programs (DTP/DTaP), which have made diphtheria rare in many parts of the world.
A nurse's primary role in diphtheria control is centered on prevention through vaccination, recognizing symptoms like a sore throat with a greyish pseudomembrane, and implementing isolation precautions for suspected cases.
What if? If a patient with an unknown vaccination history is exposed to diphtheria, a nurse would not perform a Schick test. Instead, the priority would be to assess for symptoms, obtain a throat swab for culture and PCR, and administer prophylactic antibiotics and potentially diphtheria antitoxin as per public health guidelines.

How to Approach the Question

First, identify the core of the question, which is asking for a specific test related to the disease 'Diphtheria'.
This is a factual recall question. Access your knowledge base about common diagnostic tests for infectious diseases.
Evaluate each option: Mantoux (Tuberculosis), Schick (Diphtheria), WIDAL (Typhoid), VDRL (Syphilis).
Match the disease in the question (Diphtheria) with the correct test from the options.
Confirm the match. The Schick test is historically linked to determining susceptibility to diphtheria.

Concept Tested & Keywords

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