Which test is used to detect Typhoid?

Appeared in: UP CHO - 2018

Explanation

The Widal test is a classic serological assay for diagnosing typhoid fever.
It detects agglutinating antibodies against the O (somatic) and H (flagellar) antigens of Salmonella enterica serotype Typhi.
Anti-O antibodies typically appear 6-8 days after the onset of fever, indicating an acute infection.
Anti-H antibodies appear later (10-12 days) and can persist for longer, sometimes indicating past infection or immunization.
A significant (four-fold) rise in antibody titer between two serum samples taken 7-10 days apart is considered diagnostically significant.

Option B: The Millard test is not a diagnostic laboratory test. It refers to the Millard rotation-advancement flap, a surgical technique used to repair a cleft lip.
Option C: The Kahn test is an outdated flocculation test used for the diagnosis of syphilis. It detects antibodies against cardiolipin, not Salmonella.
Option D: The Rorschach test is a psychological projective test, not a test for infectious diseases. It uses a series of inkblots to assess a person's personality characteristics and emotional functioning.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic methods for Typhoid Fever as background academic context rather than a clinical decision trigger.
While the Widal test is widely used, especially in resource-limited settings, nurses must be aware of its limitations, including false positives due to prior infections, immunization, or cross-reactivity with other bacteria.
The gold standard for diagnosing typhoid fever, particularly in the first week, is a blood culture. A nurse should ensure the sample is collected before starting antibiotic therapy to maximize the yield.
Patient education is crucial. The nurse should explain the need for a second blood sample for the Widal test to look for a rising antibody titer, which provides a more definitive diagnosis.

How to Approach the Question

First, identify the key terms in the question: 'test' and 'Typhoid'. This directs you to recall diagnostic procedures for typhoid fever.
Second, systematically evaluate each option based on your medical knowledge.
Recall that the Widal test is specifically associated with detecting antibodies against Salmonella Typhi.
Eliminate the other options by identifying their correct purpose: Millard test is a surgical procedure, Kahn test is for syphilis, and Rorschach test is a psychological assessment.
Confirming that the Widal test is the only option related to typhoid diagnosis leads to the correct answer.

Concept Tested & Keywords

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E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 267-269

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 92-94

Practise the full UP CHO - 2018

Attempt every question from this paper in a timed mock, then review the full solution for each one.