Background Lumbar puncture (LP) is usually performed when there is a clinical suspicion of meningitis in babies with suspected sepsis. Meningitis can be challenging to diagnose in preterm babies.

Aim To audit the indications and outcomes of LPs performed in preterm babies (<37+0 weeks) in a tertiary neonatal unit.

Methods A list of preterm babies who had an LP was obtained from the Microbiology Department between 01/01/2010 and 31/12/2013. The Badger electronic patient record and hospital blood results systems were reviewed to collect the data.

Results In the last 4 years we had 2618 preterm babies admitted to the neonatal unit. 98 LPs were performed in 89 preterm babies. The reasons for LPs were; (a) raised CRP in 60 cases (median CRP was 65), (b) positive blood culture in 28 cases, (c) abnormal neurology in 13 cases, (d) other reasons in 13 cases. In some cases, an LP was indicated by a combination of these factors. There were two positive cultures; one with Group B Streptococcus and another with Serratia Marcescens. At discharge, 5 had a diagnosis of meningitis based on microscopy and/or culture.

Conclusion The predominant indication for LPs in preterm babies was a raised CRP followed by a positive blood culture. We only isolated organisms from two samples. Diagnosing meningitis in preterm babies remains challenging but should always be suspected in the presence of a raised CRP and positive blood culture.