Does urgent cerebrospinal fluid (CSF) analysis After-Hours alter patient management?

Abstract

Aim After-hours CSFs result in additional laboratory costs due to on-call scientist call-backs. We analysed whether CSF Gram stain/ cell count altered patient management overnight. Methods Relevant data were retrospectively extracted from the medical records of all patients whose CSFs were analysed after-hours. Results During the 8 month period there were 71 (0.3/day) callbacks. Age range was 0-79 years; 20% were children. Eighty-six percent had normal CSF white cell count/gram stain; 7% had positive PCR/culture. LP indications included meningitis/encephalitis (44%), exclusion of CNS infection (42%) and subarachnoid haemorrhage (SAH) (14%). Initial CSF analysis altered management in 51% (treatment changes, length of hospitalisation and aided making a definitive alternative diagnosis). Management was only altered with the final CSF results in 37% and was based on non-microbiological parameters in 11%. Discussion Overall we observed no clinical parameters that guided appropriateness of LP call-backs. However, in patients empirically treated, especially in children, urgent LP did not result in management changes. Similarly, call-backs were inappropriate when LPs were performed for non-infective indications. An algorithm for call-backs may be useful, however, this seems difficult to accomplish secondary to the variability in ordering practises. Further study is needed to determine if delay results in significant degradation in CSF parameters.