title: Traumatic lumbar punctures in neonates: test performance of the cerebrospinal fluid white blood cell count.
abstract: BACKGROUND
  Cerebrospinal fluid (CSF) findings are often used to diagnose meningitis in neonates given antibiotics before the lumbar puncture is performed. Traumatic lumbar punctures are common and complicate interpretation of CSF white blood cell counts. The purpose of this study is to evaluate the diagnostic utility of adjusting CSF white blood cell counts based on CSF and peripheral red blood cell counts.
  
  
  METHODS
  Cohort study of lumbar punctures performed between 1997 and 2004 at 150 neonatal intensive care units managed by the Pediatrix Medical group. Traumatic lumbar punctures were defined as CSF specimens with > or =500 red blood cells/mm. CSF white blood cell counts were adjusted downward for traumatic lumbar punctures using several commonly used methods. We calculated sensitivity, specificity, likelihood ratios, and area under the receiver operating characteristic curve of unadjusted and adjusted CSF white blood cell counts for predicting meningitis in neonates with traumatic lumbar punctures.
  
  
  RESULTS
  Of 6374 lumbar punctures, 2519 (39.5%) were traumatic. 114/6374 (1.8%) were positive for meningitis; 50 neonates with traumatic lumbar punctures had meningitis. The areas under the receiver operating characteristic curve for white blood cell count unadjusted and adjusted by all methods were similar.
  
  
  CONCLUSIONS
  Adjustment of CSF white blood cell counts to account for increased red cells does not improve diagnostic utility. Adjustment can result in loss of sensitivity with marginal gain in specificity. Adjustment of WBC counts in the setting of a traumatic lumbar puncture does not aid in the diagnosis of bacterial and fungal meningitis in neonates.
authors.affiliation: Department of Pediatrics, Duke University, Durham, NC, USA.
authors.forename: Rachel G
authors.initials: RG
authors.lastname: Greenberg
authors.forename: P Brian
authors.initials: PB
authors.lastname: Smith
authors.forename: C Michael
authors.initials: CM
authors.lastname: Cotten
authors.forename: M Anthony
authors.initials: MA
authors.lastname: Moody
authors.forename: Reese H
authors.initials: RH
authors.lastname: Clark
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Benjamin
mesh_terms: D002555:Cerebrospinal Fluid / Q000166:cytology; D015331:Cohort Studies; D004906:Erythrocyte Count; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D007958:Leukocyte Count; D007964:Leukocytosis / Q000134:cerebrospinal fluid*; D008297:Male; D008581:Meningitis / Q000097:blood / Q000134:cerebrospinal fluid* / Q000175:diagnosis / Q000382:microbiology; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013129:Spinal Puncture / Q000009:adverse effects*; D018709:Statistics, Nonparametric