Schick test is used to diagnose?

Appeared in: IGNOU PB Bsc Nsg Entrance-2017

Explanation

The Schick test is a specific in-vivo test used to determine a person's susceptibility to Diphtheria.
It is a neutralization test where a small amount of diphtheria toxin is injected into the skin.
A positive reaction, indicated by redness and swelling, signifies that the individual lacks sufficient antibodies to neutralize the toxin and is therefore susceptible to the disease.
A negative reaction (no skin change) indicates the presence of protective antibodies, meaning the person is immune.

Option A: Measles is a viral disease caused by the measles virus. Diagnosis is confirmed by detecting measles-specific IgM antibodies in serum or by RT-PCR, not by a skin test like the Schick test.
Option B: Mumps is a viral infection. It is diagnosed based on clinical symptoms (like parotitis) and confirmed with serology (IgM antibodies) or viral detection through PCR.
Option C: Rubella (German measles) is a viral illness. Diagnosis relies on serological tests for rubella-specific IgM and IgG antibodies.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic tests for infectious diseases as background academic context rather than a clinical decision trigger.
Understanding the principle of the Schick test is fundamental to grasping toxin-antitoxin interactions and the concept of in-vivo immunity testing, even though the test is now rarely used due to high vaccination rates.
A nurse's primary role in diphtheria prevention is through administering the DTaP/Tdap vaccine series and educating families on the importance of maintaining the immunization schedule.
What if? If a person from a region with a diphtheria outbreak and an unknown vaccination history presents with a severe sore throat and a greyish membrane in the pharynx, the priority is not the Schick test but immediate isolation, administration of diphtheria antitoxin, and antibiotic therapy, while laboratory confirmation is pending.

How to Approach the Question

Identify the keyword in the question stem: 'Schick test'.
This is a factual recall question that requires you to link a specific diagnostic test to a disease.
Recall or deduce the purpose of various historical and current diagnostic tests for infectious diseases.
Associate the 'Schick test' with Diphtheria. This is a classic pairing in microbiology and community health nursing.
Eliminate the other options. Measles, Mumps, and Rubella are viral diseases often grouped under the MMR vaccine and are diagnosed using modern serological or molecular methods, not a historical skin test for a bacterial toxin.

Concept Tested & Keywords

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E6 Microbiology Applied AnjuDhir 3e Part 2 p. 106-108

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