title: Performance evaluation of the Alere PIMA CD4 test for monitoring HIV-infected individuals in resource-constrained settings.
abstract: BACKGROUND
  Enumeration of CD4+ T-lymphocytes is important in the management of HIV. However, standard laboratory systems based on flow cytometry are expensive, complicated, and thus unavailable to most resource-limited settings where a low-cost and fully automated point-of-care CD4 testing system is required. In attempts to address this issue, a study was conducted to validate the Alere PIMA point-of-care CD4 test.
  
  
  METHODS
  Duplicate values of the absolute number of CD4+ T-lymphocytes in 203 HIV-infected blood samples obtained using the PIMA system were compared with the two predicate single-platform FACSCount and the dual-platform FACSCan (Becton Dickinson Biosciences).
  
  
  RESULTS
  The overall absolute CD4+ T-lymphocyte count obtained using the PIMA system correlated highly with the FACSCount (r = 0.957; mean bias, -54.2 cells/μL; limit of agreement, -190.9 to +82.5 cells/μL) and the FACSCan (r = 0.957; mean bias -44.0 cells/μL; limit of agreement, -179.7 to +91.6 cells/μL). Good correlation and low biases were also observed for samples with CD4+ T-lymphocyte count ranges of 0 to 200 and 0 to 350 cells/μL. Additionally, there was no significant difference in absolute CD4+ T-lymphocyte counts noted between the duplicate samples using the PIMA system.
  
  
  CONCLUSIONS
  This new point-of-care product is a simple and reliable system and should contribute significantly to the simplification of performing CD4 testing and thus increase access for patients in resource-limited settings. The inability to obtain values for the frequency (%) of CD4+ T-lymphocyte count is one limitation of the PIMA system, the addition of which would be of value for clinical staging or monitoring in HIV-infected pediatric patients.
authors.affiliation: Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Kasama
authors.initials: K
authors.lastname: Sukapirom
authors.forename: Nattawat
authors.initials: N
authors.lastname: Onlamoon
authors.forename: Charin
authors.initials: C
authors.lastname: Thepthai
authors.forename: Korakot
authors.initials: K
authors.lastname: Polsrila
authors.forename: Boonrat
authors.initials: B
authors.lastname: Tassaneetrithep
authors.forename: Kovit
authors.initials: K
authors.lastname: Pattanapanyasat
mesh_terms: D018791:CD4 Lymphocyte Count / Q000191:economics / Q000379:methods*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005434:Flow Cytometry; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D016014:Linear Models; D019095:Point-of-Care Systems; D015203:Reproducibility of Results; D013785:Thailand