title: Evaluation of cell counting and leukocyte differentiation in cerebrospinal fluid controls using hematology analyzers by the German Society for Clinical Chemistry and Laboratory Medicine.
abstract: BACKGROUND
  Manual cell counting in cerebrospinal fluid (CSF) is technique-dependent, time-consuming, and thus costly and prone to inter-operator variability and low precision. Flow cytometry (FCM) with fast hematology analyzers (HAs) appears to improve accuracy and precision of CSF cell analysis; rapid CSF cell analysis is especially needed in emergency laboratories. Ten external trials of the German Society for Clinical Chemistry and Laboratory Medicine evaluated FCM with Coulter (LH750, 755), Abbott CD3200, CD3500, CD3700, CD4000, Sapphire, ADVIA120 CSF assay, and Sysmex XE-2100 single platform analyzers.
  
  
  METHODS
  CSF controls were produced using native blood leukocytes and erythrocytes, resembling CSF and thus rendering the trials feasible and allowing comparison with native manual counting in a Fuchs-Rosenthal chamber and FACScan-CD45-CD14 dual platform analysis, which was used as the reference method. Statistical evaluation was performed using Passing/Bablok regression analysis.
  
  
  RESULTS
  Our evaluation revealed significant differences with respect to target values in leukocyte and erythrocyte counts, as well as leukocyte differentiation. These differences were attributed to inaccuracies produced by the HAs, due to blank correction in connection with impedance analysis, leukocyte loss, especially through monocyte injury due to the erythrocyte lysing agent, incomplete erythrocyte lysis, ADVIA cell sphering, cell differentiation using algorithms and peroxidase activity. Erythrocyte counting in the CSF controls was inaccurate with the Coulter and ADVIA analyzers.
  
  
  CONCLUSIONS
  Evaluation of HAs by means of the CSF controls revealed inaccuracies in cell counting and leukocyte differentiation. Analyzer techniques, used for CSF cell assays, therefore need to be improved.
authors.affiliation: Abteilung für Klinische Chemie und Molekulare Diagnostik mit Referenzlabor für Liquordiagnostik, Universitätsklinikum Giessen and Marburg, Marburg, Germany.
authors.forename: Tilmann O
authors.initials: TO
authors.lastname: Kleine
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Nebe
authors.forename: Christa
authors.initials: C
authors.lastname: Löwer
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lehmitz
authors.forename: Wolf-Jochen
authors.initials: WJ
authors.lastname: Geilenkeuser
authors.forename: Rolf
authors.initials: R
authors.lastname: Kruse
authors.forename: Alexandra
authors.initials: A
authors.lastname: Dorn-Beineke
mesh_terms: D002454:Cell Differentiation; D002555:Cerebrospinal Fluid / Q000166:cytology*; D019411:Clinical Laboratory Techniques; D004912:Erythrocytes / Q000166:cytology; D005434:Flow Cytometry / Q000295:instrumentation*; D005858:Germany; D006098:Granulocytes / Q000166:cytology; D006801:Humans; D007958:Leukocyte Count / Q000295:instrumentation*; D007962:Leukocytes / Q000166:cytology*; D008214:Lymphocytes / Q000166:cytology; D009000:Monocytes / Q000166:cytology; D012955:Societies, Medical