Analysis of cerebrospinal fluid for xanthochromia in the investigation of subarachnoid haemorrhage: experience of a state-wide, tertiary referral trauma centre

Introduction: Subarachnoid haemorrhage (SAH) is associated with high mortality and morbidity. To aid diagnosis, cerebrospinal fluid (CSF) can be examined for xanthochromia (yellow discoloration, indicating the presence of bilirubin). The Department of Pathology, Royal Hobart Hospital offers a state-wide service for the detection of CSF xanthochromia. CSF xanthochromia results from the current service were audited to assess clinical utility.

Methods: We reviewed CSF xanthochromia results from samples received over a two-year period. Data reviewed included the date and time of: initial Non Contrast-Computed Tomography of the Brain (NC-CTB) scan, CSF sample collection, sample receipt in the laboratory, release of result to the clinician, and when the patient was discharged from the hospital. Xanthochromia in CSF was determined by spectrophotometry.

Results: Sixty-nine CSF samples were tested for xanthochromia. In no sample was xanthochromia positively identified by spectrophotometry. No patient had a diagnosis of SAH by NCCTB. Three-quarters (74%) of these samples were analysed within normal working hours. For these samples, the median time for sample analysis and reporting of the result after receipt into the laboratory was 4 hours. Median (range) time from onset of symptoms to CSF collection was 32 (10-241) hours. One-third (29%) of patients were discharged from the hospital 28-61 (median 20) hours prior to the CSF xanthochromia result being reported. Eighteen samples were analysed 'out of hours' as urgent requests. All patients except 1 were discharged after receiving the negative CSF xanthochromia result (median 3, range <1-282 hours).

Conclusion: Our study confirms the low detection rate of SAH by CSF xanthochromia. A significant number of patients being discharged prior to release of the xanthochromia result were identified. A more targeted approach to the utilisation of CSF xanthochromia testing requested during normal working hours should be pursued.