title: Comparative analysis of cerebrospinal fluid adenosine deaminase activity in meningitis.
abstract: OBJECTIVE
  The purpose is to determine the cut-off value of adenosine deaminase (ADA) activity in cerebrospinal fluid (CSF) of patients with tuberculous and non-tuberculous meningitis, and to assess its value in differential diagnosis.
  
  
  METHODS
  This study was conducted in 91 patients with meningitis in two university hospitals in Turkey. 24 patients had tuberculous meningitis (TBM), 25 purulent meningitis (PM), 25 aseptic meningitis (AM) and 17 neurobrucellosis (BM). ADA activity of CSF was quantified by colorimetry.
  
  
  RESULTS
  In our study, mean ADA values in CSF were 28.34 ± 14.83 IU/L in TB cases, 8.71 ± 5.83 IU/L in BM, 6.18 ± 2.54 IU/L in PM and 3.43 ± 3.48 U/L in AM cases. If we accept for CSF ADA an activity cut-off value of 12.5 IU/L for differential diagnosis of TBM and BM, its sensitivity was 92% and specificity was 88%. If we accept 12.35 IU/L for differential diagnosis of TBM and PM, its sensitivity was 92% and specificity was 100%. If we accept 6.45 IU/L for differential diagnosis of TBM and AM, its sensitivity was 100% and specificity was 92%. Additionally, we examined the cases after dividing them into two groups, viz. TB and non-TB. If we accept an ADA activity cut-off level of 11 IU/L for differential diagnosis of TB and non-TB by applying ROC analysis, its sensitivity was 92% and specificity was 90%.
  
  
  CONCLUSIONS
  The sensitivity and specificity for CSF ADA activity are markedly high in differential diagnosis of TB from non-TB. Hence CSF ADA activity may be used as a simple, cost-effective and reliable test for early differential diagnosis of TB.
authors.affiliation: Harran Univesity School of Medicine, Department of Infectious Diseases and Clinical Microbiology, 63300 Sanliurfa, Turkey. hasankarsen@hotmail.com
authors.forename: Hasan
authors.initials: H
authors.lastname: Karsen
authors.forename: Suda Tekin
authors.initials: ST
authors.lastname: Koruk
authors.forename: Mustafa Kasim
authors.initials: MK
authors.lastname: Karahocagil
authors.forename: Celal
authors.initials: C
authors.lastname: Calisir
authors.forename: Fatma Corcu
authors.initials: FC
authors.lastname: Baran
mesh_terms: D000243:Adenosine Deaminase / Q000134:cerebrospinal fluid*; D000293:Adolescent; D000328:Adult; D002006:Brucellosis / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000201:enzymology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008582:Meningitis, Aseptic / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000201:enzymology; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D014390:Tuberculosis, Meningeal / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000201:enzymology
chemical_list: D000243:Adenosine Deaminase