title: Cerebrospinal fluid/blood glucose ratio as an indicator for bacterial meningitis.
abstract: BACKGROUND
  Bacterial meningitis is an emergent disease requiring prompt diagnosis and treatment with appropriate antimicrobials. Although the lumbar puncture is widely used as a diagnostic tool for bacterial meningitis, it remains unclear which value in cerebrospinal fluid (CSF) analysis in emergency laboratory tests precisely predicts the presence of bacterial meningitis.
  
  
  METHODS
  This is a single-center, retrospective review of medical records to determine which emergency laboratory CSF test results are useful for predicting bacterial meningitis. The diagnosis of meningitis is made when the white blood cell count in CSF exceeds 5 cells/μL, while the diagnosis of bacterial meningitis additionally requires the growth of a pathogen from a CSF culture or the identification of a pathogen in Gram staining of CSF specimen.
  
  
  RESULTS
  We identified 15 patients with bacterial meningitis and 129 patients with aseptic meningitis. While neutrophil-predominant pleocytosis and a decreased glucose level in CSF can predict the presence of bacterial meningitis, the CSF/blood glucose ratio is more precise (optimal cut-off=0.36, sensitivity=92.9%, specificity=92.9%, area under the curve=.97) even after administration of antimicrobials prior to examination in the emergency department.
  
  
  CONCLUSIONS
  This study suggests that the CSF/blood glucose ratio may be a better single indicator for bacterial meningitis. Since the CSF glucose and blood glucose values are promptly and easily obtained from a lumbar puncture, the CSF/blood glucose ratio should be considered as a timely diagnostic indicator of bacterial meningitis. It may also help exclude the diagnosis of bacterial meningitis especially in cases in which no microorganisms can be cultured.
authors.affiliation: Department of Emergency Rescue, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan. Electronic address: tamune-tky@umin.ac.jp.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Tamune
authors.affiliation: Department of Emergency Rescue, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeya
authors.affiliation: Department of Emergency Rescue, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Wakako
authors.initials: W
authors.lastname: Suzuki
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Tagashira
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Takaie
authors.initials: T
authors.lastname: Kuki
authors.affiliation: Department of Infection Prevention, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Honda
authors.affiliation: Department of Mental Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid; D001786:Blood Glucose / Q000378:metabolism*; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D005260:Female; D005947:Glucose / Q000134:cerebrospinal fluid*; D006801:Humans; D007958:Leukocyte Count; D007964:Leukocytosis / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000209:etiology; D008297:Male; D008582:Meningitis, Aseptic / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis; D016920:Meningitis, Bacterial / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D005947:Glucose