title: Rapid, accurate and non-invasive detection of cerebrospinal fluid leakage using combined determination of beta-trace protein in secretion and serum.
abstract: BACKGROUND
  beta-Trace protein (Btp) has been proposed as a valuable marker of cerebrospinal fluid (CSF) leakage overcoming the drawbacks of beta-2-transferrin (B-2Tr) determination. However, there is still controversy about the appropriate cut-offs to be used (range 0.35-6 mg/L). The aim of the study was to evaluate cut-offs of Btp determination for detection CSF leakage. Further, we assessed whether the Btp secretion to serum ratio (Btp-sec/ser-ratio) would add diagnostic value.
  
  
  METHODS
  Prospective study in patients with suspected CSF leakage. Quantitative determination of Btp in secretion and serum (Dade-Behring) and qualitative measurement of B-2-Tr in secretion and serum. Results were assessed in view of clinical data. Cut-offs and diagnostic characteristics were determined by ROC analysis.
  
  
  RESULTS
  A total of 176 samples were assessed originating from 105 patients. In 43 samples CSF leakage could be confirmed. Sensitivity of B-2-Tr was 84%, specificity amounted to 100%. The area under the curve (AUC) for Btp-measurement in secretion was 0.98. At a cut-off of 0.68 mg/L, sensitivity was 100% and specificity 91%. At a cut-off of 1.11 mg/L, the specificity was 100% with a sensitivity of 93%. The Btp-sec/ser-ratio has an AUC of 0.99. Combining a 0.68 mg/L cut-off in secretion with a Btp-sec/ser-ratio cut-off of 4.9 reveals a sensitivity of 99% and a specificity of 100%.
  
  
  CONCLUSIONS
  Btp is a rapid and accurate marker for the presence of CSF leakage. Combining measurement of Btp in secretion together with determination of the Btp-sec/ser-ratio enhances the diagnostic characteristics of the Btp assay. Determination of Btp in both serum and secretion is thus recommended.
authors.affiliation: Clinical Decision Making Research Unit, Vorarlberg Institute of Vascular Investigation and Treatment, Academic Teaching Hospital, Feldkirch, Austria.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Risch
authors.forename: Ivan
authors.initials: I
authors.lastname: Lisec
authors.forename: Markus
authors.initials: M
authors.lastname: Jutzi
authors.forename: Michael
authors.initials: M
authors.lastname: Podvinec
authors.forename: Hans
authors.initials: H
authors.lastname: Landolt
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Huber
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D002555:Cerebrospinal Fluid / Q000502:physiology*; D006259:Craniocerebral Trauma / Q000134:cerebrospinal fluid*; D004423:Ear / Q000293:injuries; D005260:Female; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood / Q000134:cerebrospinal fluid*; D054834:Lipocalins; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry; D019635:Neurosurgical Procedures; D009666:Nose / Q000293:injuries; D011446:Prospective Studies; D012372:ROC Curve; D011859:Radiography; D012887:Skull Fractures / Q000134:cerebrospinal fluid / Q000000981:diagnostic imaging; D014168:Transferrin / Q000134:cerebrospinal fluid
chemical_list: D015415:Biomarkers; D054834:Lipocalins; D014168:Transferrin; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase