title: Helper T-lymphocyte count. TRAx CD4 test kit versus conventional flow cytometry.
abstract: BACKGROUND
  We evaluated a newly developed enzyme-linked immunosorbent assay system for measuring helper T-lymphocyte count.
  
  
  METHODS
  Data from 111 human immunodeficiency virus-infected injection drug users in a cohort study were analyzed by flow cytometry and independent duplicate runs of the TRAx enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The mean helper T-cell counts were 470, 480, and 506 per microliter by flow cytometry and TRAx runs 1 and 2, respectively. The correlation coefficients for TRAx runs 1 and 2 with the flow cytometry results as the dependent variable were .93 and .91, respectively. A cross-tabulation of the enzyme-linked immunosorbent assay helper T-lymphocyte counts with flow cytometry counts showed agreement of 71% and 76% when the flow count was between 201 and 500, and 88% and 90% when it was greater than 500 cells per microliter. In those samples with 200 or fewer helper T cells, agreement was 73% and 41% for each TRAx run.
  
  
  CONCLUSIONS
  The TRAx enzyme-linked immunosorbent assay system is an acceptable method for measuring helper T-lymphocyte count, but should be recalibrated for better performance at helper T-cell counts below 200 per microliter.
authors.affiliation: Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Saah
authors.forename: C
authors.initials: C
authors.lastname: Spruill
authors.forename: D R
authors.initials: DR
authors.lastname: Hoover
authors.forename: R
authors.initials: R
authors.lastname: Prevots
authors.forename: E
authors.initials: E
authors.lastname: Taylor
authors.forename: J B
authors.initials: JB
authors.lastname: Margolick
authors.forename: D
authors.initials: D
authors.lastname: Vlahov
mesh_terms: D018791:CD4 Lymphocyte Count / Q000379:methods*; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation* / Q000379:methods; D005434:Flow Cytometry / Q000379:methods*; D015658:HIV Infections / Q000276:immunology; D006801:Humans; D016131:Lymphocyte Subsets; D011933:Reagent Kits, Diagnostic; D015819:Substance Abuse, Intravenous; D006377:T-Lymphocytes, Helper-Inducer
chemical_list: D011933:Reagent Kits, Diagnostic