Supplementary Material for: Normal Values for Cerebrospinal Fluid in Neonates: A Systematic Review

<b><i>Background:</i></b> The diagnosis of neonatal meningitis often rests on microscopic and biochemical findings in the cerebrospinal fluid (CSF). There is ongoing uncertainty about age-related normal values for CSF findings in neonates, and many previous studies have included infants in whom antibiotics were administered before lumbar puncture or in whom viral meningitis was not excluded. <b><i>Methods:</i></b> A systematic search was done using MEDLINE and EMBASE to identify original studies which investigated CSF normal values in either healthy neonates or febrile neonates in whom bacterial and viral meningitis were reliably excluded. <b><i>Results:</i></b> We identified seven studies investigating 270 term and 96 preterm neonates. There were minimal differences between preterm and term neonates in the CSF white blood cell (WBC) count and glucose concentration. In contrast, the CSF neutrophil count and protein concentration were influenced by gestational and chronological age. In the four studies that reported individual patient data, in 95% of cases the CSF WBC count was &lt;12 cells/μL in preterm and &lt;10 cells/μL in term neonates, the neutrophil count was &lt;16 and 8 cells/μL, and the protein concentration was &lt;210 and 110 mg/dL, respectively. <b><i>Conclusion:</i></b> The normal range for CSF parameters in neonates is different to that in older infants, and some parameters are influenced by gestational and chronological age. CSF parameters alone are not sufficiently reliable to exclude meningitis.