title: Evaluation of a single-platform microcapillary flow cytometer for enumeration of absolute CD4+ T-lymphocyte counts in HIV-1 infected Thai patients.
abstract: BACKGROUND
  Various assays are used to enumerate peripheral blood absolute CD4+ T-lymphocytes. Flow cytometry is considered the gold standard for this purpose. However, the high cost of available flow cytometers and monoclonal antibody reagents make it difficult to implement such methods in the resource-poor settings. In this study, we evaluated a cheaper, recently developed single-platform microcapillary cytometer for CD4+ T-lymphocyte enumeration, the personal cell analyzer (PCA), from Guava Technologies.
  
  
  METHODS
  CD4+ and CD8+ T-lymphocyte counts in whole blood samples from 250 HIV-1 infected Thais were determined, using a two-color reagent kit and the Guava PCA, and compared with the results obtained with two reference microbead-based methods from Becton Dickinson Biosciences: the three-color TruCOUNT tube method and the two-color FACSCount method. Statistical correlations and agreements were determined using linear correlation and Bland-Altman analysis.
  
  
  RESULTS
  Absolute CD4+ T-lymphocyte counts obtained using the Guava PCA method highly correlated with those obtained using TruCOUNT method (R(2) = 0.95, mean bias +13.1 cells/microl, limit of agreement [LOA]-117.9 to +144.1 cells/microl) and the FACSCount method (R2 = 0.94, mean bias = +33.2 cells/microl, LOA-101.8 to +168.3 cells/microl). Absolute CD8+ T-lymphocyte counts obtained using the Guava PCA method also highly correlated with those obtained with the two reference methods (R(2) = 0.92 and 0.88, respectively).
  
  
  CONCLUSIONS
  This study shows that the enumeration of CD4+ T-lymphocytes using the Guava microcapillary cytometer PCA method performed well when compared with the two reference bead-based methods. However, like the two reference methods, this new method needs substantial technical expertise.
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: Yuwadee
authors.initials: Y
authors.lastname: Phuang-Ngern
authors.forename: Surada
authors.initials: S
authors.lastname: Lerdwana
authors.forename: Punneeporn
authors.initials: P
authors.lastname: Wasinrapee
authors.forename: Natthaga
authors.initials: N
authors.lastname: Sakulploy
authors.forename: Egarit
authors.initials: E
authors.lastname: Noulsri
authors.forename: Charin
authors.initials: C
authors.lastname: Thepthai
authors.forename: Janet M
authors.initials: JM
authors.lastname: McNicholl
mesh_terms: D018791:CD4 Lymphocyte Count / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003362:Cost-Benefit Analysis; D005434:Flow Cytometry / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D006801:Humans; D007202:Indicators and Reagents / Q000592:standards; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013785:Thailand
chemical_list: D007202:Indicators and Reagents