title: Evaluation of the interference of hemoglobin, bilirubin, and lipids on Roche Cobas 6000 assays.
abstract: BACKGROUND
  Pre-analytical error accounts for major total laboratory errors. We assessed the impacts of hemolysis, icterus, and lipemia on laboratory tests on Roche Cobas 6000.
  
  
  METHODS
  Various concentrations of hemoglobin, bilirubin, or Intralipid® were added into the plasma to simulate hemolytic, icteric, or lipemic samples. The analytes were then measured on Roche Cobas 6000 and the change of the analyte concentrations was determined.
  
  
  RESULTS
  For most of the chemistry assays, our data were in a good agreement with Roche package inserts. However some assays had significant interference at lower index values while others were affected at higher index than the Roche package inserts indicated. In addition, we observed the positive interference by hemolysis on ALT, lipase, total protein, potassium, and iron. Negative interference was noted on calcium and CK. Most of the immunoassays were not affected by hemoglobin, bilirubin, and lipids although there were a few exceptions. Several therapeutic drugs were affected either positively or negatively by hemolysis, icterus, or lipemia to a certain extent.
  
  
  CONCLUSIONS
  We have demonstrated some test interferences which have not been reported previously on the Cobas 6000. The implementation of the cut-off indices on Cobas 6000 would provide more accurate test result reporting.
authors.affiliation: Department of Pathology and Laboratory Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: Jing Zhang
authors.initials: JZ
authors.lastname: Ji
authors.forename: Qing H
authors.initials: QH
authors.lastname: Meng
mesh_terms: D001663:Bilirubin / Q000097:blood*; D019963:Clinical Chemistry Tests; D006454:Hemoglobins / Q000032:analysis*; D006461:Hemolysis; D006801:Humans; D008055:Lipids / Q000097:blood*
chemical_list: D006454:Hemoglobins; D008055:Lipids; D001663:Bilirubin