title: Evaluation of high resolution gel β(2)-transferrin for detection of cerebrospinal fluid leak.
abstract: BACKGROUND
  Cerebrospinal fluid (CSF) leaks are potentially life-threatening conditions that can be diagnosed by detection of β(2)-transferrin using protein electrophoresis. Another less commonly available test is β-trace protein quantitation using immunoassay. The objectives of this study were to evaluate a new immunofixation-based β(2)-transferrin test for detection of CSF leaks and to compare it to an existing agarose gel electrophoresis test and β-trace protein immunoassay.
  
  
  METHODS
  For method comparison, 63 consecutive samples from physician-ordered β(2)-transferrin tests were analyzed using two different electrophoresis methods, agarose gel fractionation followed by acid-violet staining, and high resolution agarose gel electrophoresis followed by β(2)-transferrin immunofixation. A subset of samples (16/63) were analyzed for β-trace protein. Results were compared against patient chart data for the presence of a CSF leak. Additional studies were performed to assess the stability, detection limit, and analytical specificity of the β(2)-transferrin immunofixation test.
  
  
  RESULTS
  The β(2)-transferrin immunofixation test had a sensitivity of 100 % (40/40) and specificity of 71 % (12/17) for detection of CSF leaks. By comparison, the agarose gel test had a sensitivity of 87 % (35/40) and specificity of 94 % (16/17). β-trace protein had a sensitivity of 100 % (10/10) and specificity of 86 % (5/6). Serum and saliva could be differentiated from CSF by the β(2)-transferrin immunofixation test based on their migration patterns. However, whole blood samples appeared positive for β(2)-transferrin at a threshold of ~ 4 g/L hemoglobin. At a cut-off of 3 mg/L, β-trace protein was increased in 10/10 cases with documented CSF leak and in 1/6 patients without CSF leak.
  
  
  CONCLUSIONS
  Both the new immunofixation test for β(2)-transferrin and the β-trace protein were effective at detecting CSF leaks. Users of the β(2)-transferrin immunofixation test should be cautioned against interpreting samples with blood contamination.
authors.affiliation: Division of Biochemistry, Department of Pathology and Laboratory Medicine, University of Ottawa, The Ottawa Hospital, 501 Smyth Road, Ottawa ON, Canada, K1H 8L6. cmccudde@uottawa.ca
authors.forename: Christopher R
authors.initials: CR
authors.lastname: McCudden
authors.forename: Brent A
authors.initials: BA
authors.lastname: Senior
authors.forename: Shirley
authors.initials: S
authors.lastname: Hainsworth
authors.forename: Walter
authors.initials: W
authors.lastname: Oliveira
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Silverman
authors.forename: David E
authors.initials: DE
authors.lastname: Bruns
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Hammett-Stabler
mesh_terms: D001826:Body Fluids / Q000737:chemistry* / Q000378:metabolism; D065634:Cerebrospinal Fluid Leak; D002559:Cerebrospinal Fluid Rhinorrhea / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism; D004587:Electrophoresis, Agar Gel / Q000379:methods*; D006801:Humans; D007118:Immunoassay; D007158:Immunologic Techniques; D009093:Mucus / Q000737:chemistry / Q000378:metabolism; D012680:Sensitivity and Specificity; D014168:Transferrin / Q000032:analysis* / Q000378:metabolism
chemical_list: D014168:Transferrin