Paper II — 2024 December (Supplementary) (2019 Scheme) — Q12
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Paper II
2024 December (Supplementary) (2019 Scheme) · 100 marks · 180 min
Question
How will you instruct a patient with suspected lower respiratory tract infection to collect a sputum sample.
Q124 marksShort Answers
Answer
Instructions to a patient for sputum sample collection:
Timing: collect an early-morning sample (before eating/drinking), since overnight pooling of secretions produces a more concentrated, representative sample.
Preparation: instruct the patient to rinse the mouth thoroughly with plain water before collection, to reduce contamination by oral flora/food debris.
Deep-cough technique: instruct the patient to take a few deep breaths, then cough deeply and forcefully from the chest (not merely clear the throat) to bring up sputum from the lower respiratory tract — spitting saliva alone is inadequate and produces an unsatisfactory sample.
Collection container: the expectorated sputum should be collected directly into a sterile, wide-mouthed, leak-proof container, avoiding contamination of the container’s interior/rim.
Volume: an adequate volume (typically 3–5 mL) should be collected where possible.
Supervision/privacy: collection should ideally be supervised or performed in a well-ventilated, private area (e.g., outdoors or a designated sputum collection booth) — given the risk of aerosol generation, particularly important when tuberculosis is suspected, for infection-control reasons.
Labelling and prompt transport: the container should be correctly labelled with patient identifiers, and the sample transported to the laboratory promptly (or refrigerated if any delay is unavoidable) to preserve organism viability and specimen quality.
Sputum induction: if the patient is unable to produce sputum spontaneously, sputum induction (using nebulized hypertonic saline) may be used to stimulate productive coughing, performed under appropriate infection-control precautions.
Quality check: on receipt, the laboratory should assess specimen adequacy (e.g., by Gram stain criteria — sufficient pus cells, minimal squamous epithelial cells) before proceeding with culture, to avoid processing a saliva-dominant, unsatisfactory sample.
