CSF xanthochromia: correlation with brain imaging and its usefulness as an out-of-hours test

Abstract

BackgroundSubarachnoid haemorrhage (SAH) is a spontaneous bleed into the subarachnoid space which is investigated by CT head and cerebrospinal fluid (CSF) xanthochromia. The aim of this study was to compare CSF xanthochromia with brain imaging and evaluate the need for out of hours (OOH) testing for CSF xanthochromia.MethodDischarge summaries and brain imaging of patients with positive xanthochromia screen were reviewed over 12 months retrospectively. Timings of CSF xanthochromia and hospital discharge of 30 consecutive patients with negative xanthochromia screen were also examined.ResultsFrom 289 xanthochromia requests, 23 were positive but only 2 patients had an actual bleed. In 30 consecutive negative xanthochromia results, all brain imaging results suggested no bleed. Eight of these requests were performed OOH, and as a result, 1 patient was discharged early.ConclusionsCSF xanthochromia has a poor positive predictive value (8.7%) but has a good negative predictive value (100%) for SAH. Analysis of CSF xanthochromia OOH, in patients with negative CT head, did not speed up the discharge process from the hospital.