Paper II — 2025 March (Supplementary (SAY)) (2019 Scheme) — Q12
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Paper II
2025 March (Supplementary (SAY)) (2019 Scheme) · 100 marks · 180 min
Question
A CSF sample did not reach the laboratory. Discuss the impact on patient care and how this can
be prevented.
Q124 marksShort Answers
Answer
Impact on patient care: if a CSF sample fails to reach the laboratory, the patient (typically presenting with suspected meningitis, a time-critical, potentially rapidly fatal condition) loses the opportunity for microbiological confirmation of the causative organism, meaning:
The clinician must continue empirical, broad-spectrum antibiotic therapy without the benefit of organism identification or antimicrobial susceptibility results, risking either inadequate coverage of a resistant organism or unnecessarily broad/prolonged antibiotic use.
Adjunctive therapy decisions (e.g., dexamethasone, which is genuinely evidence-based for reducing complications such as hearing loss, particularly in pneumococcal meningitis) may be made without organism-specific confirmation to guide them.
Delayed or missed diagnosis — if the specific aetiology (bacterial versus viral versus tubercular) cannot be confirmed, the patient may not receive the most appropriate targeted therapy or duration of treatment.
Given that a repeat lumbar puncture is an invasive procedure with genuine risk/discomfort, the opportunity to obtain this diagnostic information from that specific clinical episode may be genuinely lost or substantially delayed, potentially prolonging illness or worsening outcome.
Public health/epidemiological surveillance (e.g., tracking meningococcal disease for outbreak detection) also loses valuable case-level data.
Prevention:
Immediate transport of the CSF sample to the laboratory as soon as it is collected — CSF for bacterial culture should never be held, refrigerated, or delayed, since fastidious organisms causing bacterial meningitis (e.g., Neisseria meningitidis, Haemophilus influenzae) are cold-sensitive/fragile and can die in transit if delayed.
Clear ward protocols and staff training on the urgency and correct handling of CSF samples, given their invasive collection and time-critical nature.
Designated, reliable sample-transport pathways (e.g., a dedicated porter/courier system with defined turnaround targets) between wards and the microbiology laboratory, particularly for urgent/STAT samples.
Communication between ward and laboratory — the laboratory should be alerted in advance that a CSF sample is being sent, allowing prompt processing on arrival and a mechanism to flag/investigate if an expected sample fails to arrive within an expected timeframe.
Correct labelling and documentation at the time of collection, to avoid delays caused by identification/requisition discrepancies once the sample does arrive.
