title: Japanese Society for Laboratory Hematology flow cytometric reference method of determining the differential leukocyte count: external quality assurance using fresh blood samples.
abstract: BACKGROUND
  To provide target values for the manufacturers' survey of the Japanese Society for Laboratory Hematology (JSLH), accurate standard data from healthy volunteers were needed for the five-part differential leukocyte count. To obtain such data, JSLH required an antibody panel that achieved high specificity (particularly for mononuclear cells) using simple gating procedures. We developed a flow cytometric method for determining the differential leukocyte count (JSLH-Diff) and validated it by comparison with the flow cytometric differential leukocyte count of the International Council for Standardization in Haematology (ICSH-Diff) and the manual differential count obtained by microscopy (Manual-Diff).
  
  
  METHODS
  First, the reference laboratory performed an imprecision study of JSLH-Diff and ICSH-Diff, as well as performing comparison among JSLH-Diff, Manual-Diff, and ICSH-Diff. Then two reference laboratories and seven participating laboratories performed imprecision and accuracy studies of JSLH-Diff, Manual-Diff, and ICSH-Diff. Simultaneously, six manufacturers' laboratories provided their own representative values by using automated hematology analyzers.
  
  
  RESULTS
  The precision of both JSLH-Diff and ICSH-Diff methods was adequate. Comparison by the reference laboratory showed that all correlation coefficients, slopes and intercepts obtained by the JSLH-Diff, ICSH-Diff, and Manual-Diff methods conformed to the criteria. When the imprecision and accuracy of JSLH-Diff were assessed at seven laboratories, the CV% for lymphocytes, neutrophils, monocytes, eosinophils, and basophils was 0.5~0.9%, 0.3~0.7%, 1.7~2.6%, 3.0~7.9%, and 3.8~10.4%, respectively. More than 99% of CD45 positive leukocytes were identified as normal leukocytes by JSLH-Diff.
  
  
  CONCLUSIONS
  When JSLH-Diff method were validated by comparison with Manual-Diff and ICSH-Diff, JSLH-Diff showed good performance as a reference method.
authors.affiliation: The Standardization Subcommittee for Blood Cell Counting of the Japanese Society for Laboratory Hematology, Tokyo, Japan.|International University of Health & Welfare, Sanno Hospital, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawai
authors.affiliation: The Standardization Subcommittee for Blood Cell Counting of the Japanese Society for Laboratory Hematology, Tokyo, Japan.|Nihon Kohden Corporation, IVD Operations, Tokyo, Japan.|Kansai University of Health Sciences, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nagai
authors.affiliation: The Standardization Subcommittee for Blood Cell Counting of the Japanese Society for Laboratory Hematology, Tokyo, Japan.|Nippon Becton Dickinson Company, Ltd, BD, Biosciences, Tokyo, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Ogawa
authors.affiliation: The Standardization Subcommittee for Blood Cell Counting of the Japanese Society for Laboratory Hematology, Tokyo, Japan.|Kansai University of Health Sciences, Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kondo
mesh_terms: D005434:Flow Cytometry / Q000379:methods* / Q000592:standards*; D064368:Healthy Volunteers; D006405:Hematology / Q000379:methods / Q000592:standards; D006801:Humans; D017493:Leukocyte Common Antigens / Q000032:analysis; D007958:Leukocyte Count / Q000379:methods*; D007962:Leukocytes / Q000166:cytology / Q000276:immunology; D012015:Reference Standards; D012680:Sensitivity and Specificity
chemical_list: D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human
keywords: Flow cytometry; differential; external quality assurance; hematology analyzer; leukocyte; reference method; standardization