title: A reliable and inexpensive EasyCD4 assay for monitoring HIV-infected individuals in resource-limited settings.
abstract: Serial measurements of absolute CD4+ T-lymphocyte counts are required to initiate and gauge response to therapy and monitor disease progression. Hence, there is an urgent need to evaluate the accuracy and validity of low-cost CD4+ T-cell count assays. Tripotassium EDTA blood specimens from HIV-infected individuals were studied using a novel flow cytometric assay (EasyCD4 assay; Guava Technologies, Hayward, CA) in comparison with standard flow cytometry (FACSCount; Becton Dickinson Immunocytometry Systems, San Jose, CA). The sensitivity, specificity value by EasyCD4 assay in enumerating absolute CD4+ T-cell counts of less than 200 cells/microL were 95% and 100%, respectively. Bland-Altman analysis showed close agreement, with the EasyCD4 assay yielding CD4+ T-cell counts a mean difference of -26 cells/microL (95% confidence interval, -96 to 44 cells/microL) higher than by flow cytometry. Our data suggest that EasyCD4 assay could be a useful alternative assay to conventional flow cytometry, may be appropriate for use in resource-limited settings.
authors.affiliation: YRG Centre for AIDS Research and Education, Chennai, India. bala@yrgcare.org
authors.forename: Pachamuthu
authors.initials: P
authors.lastname: Balakrishnan
authors.forename: Suniti
authors.initials: S
authors.lastname: Solomon
authors.forename: Janardhanan
authors.initials: J
authors.lastname: Mohanakrishnan
authors.forename: Anitha J
authors.initials: AJ
authors.lastname: Cecelia
authors.forename: Nagalingeswaran
authors.initials: N
authors.lastname: Kumarasamy
authors.forename: Kailapuri G
authors.initials: KG
authors.lastname: Murugavel
authors.forename: Bhavani
authors.initials: B
authors.lastname: Venkatakrishnan
authors.forename: Sunil S
authors.initials: SS
authors.lastname: Solomon
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Crowe
authors.forename: Aylur K
authors.initials: AK
authors.lastname: Ganesh
authors.forename: Sadras P
authors.initials: SP
authors.lastname: Thyagarajan
authors.forename: Timothy
authors.initials: T
authors.lastname: Flanigan
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Mayer
mesh_terms: D000293:Adolescent; D000328:Adult; D018791:CD4 Lymphocyte Count / Q000191:economics / Q000379:methods*; D002648:Child; D003365:Costs and Cost Analysis; D005434:Flow Cytometry / Q000379:methods; D015658:HIV Infections / Q000175:diagnosis / Q000276:immunology*; D006801:Humans; D007194:India; D008875:Middle Aged; D015166:Monitoring, Immunologic; D015203:Reproducibility of Results; D040841:Resource Allocation