title: New BD FACSCount CD4 reagent system for simultaneous enumeration of percent and absolute CD4 T-lymphocytes in HIV-1-infected pediatric patients.
abstract: BACKGROUND
  Absolute CD4+ T-lymphocyte counts are used in the initiation and monitoring of antiretroviral therapy in HIV-infected patients. Becton Dickinson's (BD) FACSCount system was introduced 12 years ago as a dedicated instrument for enumeration of absolute CD4+ T-lymphocytes. However, this system does not provide percent CD4+ T-lymphocyte that is the required monitoring parameter in pediatric patients. We evaluated a new BD FACSCount CD4 software and reagents for simultaneous percent and absolute CD4+ T-lymphocytes in HIV-infected blood.
  
  
  METHODS
  Percent and absolute CD4+ T-lymphocytes in 149 HIV-infected blood samples were determined using a new FACSCount system. Results of percent and absolute CD4+ T-lymphocytes were compared between the dual-platform (DP) method, using BD FACScan flow cytometer plus hematology analyzer and the standard FACSCount system. Correlation and agreement were analyzed using linear regression and Bland-Altman analysis.
  
  
  RESULTS
  Percent CD4+ T-lymphocyte values obtained from the new FACSCount system correlated well with DP FACScan method (r2 = 0.977, P < 0.0001). Mean bias was only -0.36% [limit of agreement (LOA): -2.52% to +1.80%] and percent similarity was 101.36%. For absolute CD4+ T-lymphocyte, the new system correlated highly with standard FACSCount system (r2 = 0.986, P < 0.0001), with a percent similarity of 98.2. Mean bias was +3.39 cells/microl with LOA of -52.53 cells/mul to +59.31 cells/microl.
  
  
  CONCLUSIONS
  This new FACSCount system is a simple and reliable system for enumeration of absolute and percent CD4+ T-lymphocytes. Having one system giving both results should reduce the cost and thus increase access to CD4 testing for pediatric and adult patients.
authors.affiliation: Center of Excellence for Flow Cytometry, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. grkpy@mahidol.ac.th
authors.forename: Kovit
authors.initials: K
authors.lastname: Pattanapanyasat
authors.forename: Kasama
authors.initials: K
authors.lastname: Sukapirom
authors.forename: Laddawan
authors.initials: L
authors.lastname: Kowawisatsut
authors.forename: Charin
authors.initials: C
authors.lastname: Thepthai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D018791:CD4 Lymphocyte Count / Q000379:methods*; D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D002648:Child; D002675:Child, Preschool; D005434:Flow Cytometry / Q000379:methods*; D015658:HIV Infections / Q000276:immunology* / Q000473:pathology* / Q000821:virology; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D007202:Indicators and Reagents; D007223:Infant; D008875:Middle Aged; D012044:Regression Analysis; D012984:Software
chemical_list: D007202:Indicators and Reagents