A nurse is preparing to collect a throat swab for culture from a child with suspected pharyngitis, from which site should the specimen be collected?

1. A

   Tongue tip

2. B

   Posterior pharyngeal wall

3. C

   Buccal mucosa

4. D

   Hard palate

Appeared in: RML MAINS 2025

Explanation

• Pharyngitis is the inflammation of the pharynx, located at the back of the throat.
• The posterior pharyngeal wall and tonsillar areas are the primary sites of infection and inflammation.
• Pathogens causing pharyngitis, like Group A Streptococcus, are most concentrated in this area.
• Collecting the sample from this site maximizes the diagnostic yield and accuracy of the culture.
• Guidelines specify swabbing the posterior pharynx and tonsillar pillars while avoiding other oral surfaces.

Why Other Options Were Wrong

• Option A: The tongue tip is part of the anterior oral cavity and is not the site of infection for pharyngitis. Swabbing here would collect saliva and normal oral bacteria, leading to a non-diagnostic or contaminated sample.
• Option C: The buccal mucosa (inner cheek) is not inflamed in pharyngitis. It is colonized by a high concentration of normal oral flora which would contaminate the specimen and interfere with the identification of the actual pathogen.
• Option D: The hard palate (the bony roof of the mouth) is not involved in the inflammatory process of pharyngitis. A swab from this site would not contain the pathogens causing the sore throat.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to The question tests the knowledge of the correct anatomical site for collecting a throat swab specimen for a culture in a patient with suspected pharyngitis to guide bedside assessment, documentation, and the next nursing action.
• Accurate specimen collection is critical for diagnosing bacterial pharyngitis, particularly from Group A Streptococcus (GAS).
• A correct diagnosis allows for appropriate antibiotic treatment, which prevents serious complications like rheumatic fever and acute glomerulonephritis.
• A contaminated sample can lead to a false-negative result, causing a delay in treatment and potentially allowing complications to develop.

How to Approach the Question

• Identify the core procedure in the question: collecting a throat swab for pharyngitis.
• Recall the anatomy of the throat and the definition of pharyngitis (inflammation of the pharynx).
• Understand the goal of a culture: to isolate the specific pathogen causing the infection.
• Consider where the pathogen would most likely be located. Since the infection is in the pharynx, the sample must come from that area.
• Evaluate the options based on their anatomical location. The tongue tip, buccal mucosa, and hard palate are all parts of the oral cavity but are not the pharynx.
• Conclude that the posterior pharyngeal wall is the only option that represents the actual site of infection.

Concept Tested & Keywords

• Concept Tested: The question tests the knowledge of the correct anatomical site for collecting a throat swab specimen for a culture in a patient with suspected pharyngitis.
• Stem keywords: throat swab, culture, pharyngitis, specimen collection
• Lead-in keywords: from which site
• Clinical cues: child with suspected pharyngitis

Question ID

QdrkFrZmL9o1eoUfUcJr5t

Copy ID

Reference Book

E6 Microbiology Essentials Sastry 4e Part 2 p. 126-128