title: Cerebrospinal fluid angiotensin-converting enzyme for diagnosis of neurosarcoidosis.
abstract: BACKGROUND
  Neurosarcoidosis (NS) is a rare condition that may mimic central nervous system (CNS) infection, neoplasia and other inflammatory disorders of the CNS such as multiple sclerosis, encephalitis and vasculitis. Diagnosis is challenging in cases with minimal or absent systemic involvement. Cerebrospinal fluid (CSF) angiotensin-converting enzyme (c-ACE) has been claimed as a valuable diagnostic tool for NS. However, there is little data evaluating its performance in routine clinical practice.
  
  
  RESULTS
  We performed a monocentric, retrospective, chart-based study including all patients investigated with a lumbar puncture and c-ACE dosage for suspected NS between 01/01/2006 and 31/12/2012 at the Geneva University Hospital. Receiver-operating characteristic (ROC) curve and area under the curve (AUC) were performed to calculate the optimal cut-off value of c-ACE and to determine the discriminative ability of c-ACE. Of the 440 patients included in the study, 9 were diagnosed with NS on the basis of tissue biopsy. Mean c-ACE was not significantly different between NS and non-NS patients. With a cut-off value of 2 (0-2 vs ≥3), sensitivity and specificity of c-ACE were 66.7% and 67.3%, respectively.
  
  
  CONCLUSIONS
  In our clinical setting, the sensitivity and specificity of c-ACE for NS diagnosis were relatively poor and of little clinical utility.
authors.affiliation: Department of Clinical Neurosciences, Division of Neurology, Unit of Neuroimmunology and Multiple Sclerosis, University Hospital of Geneva, Switzerland. Electronic address: claire.bridel@hcuge.ch.
authors.forename: Claire
authors.initials: C
authors.lastname: Bridel
authors.affiliation: Quality of Care Unit, University Hospital of Geneva, Switzerland. Electronic address: delphine.courvoiser@hcuge.ch.
authors.forename: Delphine S
authors.initials: DS
authors.lastname: Courvoisier
authors.affiliation: Department of Genetics and Laboratory Medicine, Laboratory Medicine Service, University Hospital of Geneva, Switzerland. Electronic address: nicolas.vuilleumier@hcuge.ch.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vuilleumier
authors.affiliation: Department of Clinical Neurosciences, Division of Neurology, Unit of Neuroimmunology and Multiple Sclerosis, University Hospital of Geneva, Switzerland; Department of Genetics and Laboratory Medicine, Laboratory Medicine Service, University Hospital of Geneva, Switzerland. Electronic address: patrice.lalive@hcuge.ch.
authors.forename: Patrice H
authors.initials: PH
authors.lastname: Lalive
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000134:cerebrospinal fluid; D002493:Central Nervous System Diseases / Q000134:cerebrospinal fluid* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000134:cerebrospinal fluid*; D012189:Retrospective Studies; D012507:Sarcoidosis / Q000134:cerebrospinal fluid* / Q000175:diagnosis*
chemical_list: D015415:Biomarkers; D007703:Peptidyl-Dipeptidase A
keywords: Angiotensin-converting enzyme; Cerebrospinal fluid; Granulomatous diseases; Inflammatory diseases of the central nervous system; Neurosarcoidosis