title: Comparison of 5 flow cytometric immunophenotyping systems for absolute CD4+ T-lymphocyte counts in HIV-1-infected patients living in resource-limited settings.
abstract: Enumeration of CD4+ T lymphocytes is important in management of HIV-infected patients. However, CD4 testing by current gold standard bead-based flow cytometer (FCM) system is expensive for developing countries. This study compared 2 affordable volumetric FCMs with the 3 predicate FCM systems. CD4+ T-lymphocyte counts on blood samples from 150 HIV-1-infected Thai patients were determined in parallel by 5 FCM systems: the 2 single-platform volumetric FCM systems, Guava and CyFlow(green); the 2 standard single-platform bead-based systems (2-color FACSCount and the TriTEST/TruCOUNT tube using a FACSCalibur FCM); and the dual-platform TriTEST system. Correlation and agreement were analyzed using linear regression and Bland-Altman analysis. Results from these 2 volumetric systems gave similar results and excellent correlation: R2 > 0.93; mean biases ranged from +6.3 to +24.1 cells per microliter more for the Guava. In contrast, the CyFlow(green) showed the lowest values with R2 > 0.97; mean biases ranged from -9.8 to -27.6 cells per microliter. This indicates that the absolute CD4+ T-lymphocyte counts determined by CyFlow(green) are < FACSCount < DP TriTEST < TriTEST/TruCOUNT < Guava. Although the use of these 2 volumetric FCMs could make CD4+ T-lymphocyte enumeration more affordable in resource-poor settings, variations among these systems should be considered if these are to be interchanged.
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: Kasama
authors.initials: K
authors.lastname: Sukapirom
authors.forename: Surada
authors.initials: S
authors.lastname: Lerdwana
authors.forename: Charin
authors.initials: C
authors.lastname: Thepthai
authors.forename: Boonrat
authors.initials: B
authors.lastname: Tassaneetrithep
mesh_terms: D018791:CD4 Lymphocyte Count / Q000379:methods*; D005434:Flow Cytometry / Q000191:economics / Q000295:instrumentation*; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology; D017048:Health Care Costs; D006801:Humans; D016130:Immunophenotyping / Q000191:economics / Q000295:instrumentation*; D016014:Linear Models; D011203:Poverty; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity