title: Evaluation of a dry format reagent for CD4+ and CD8+ T-cell enumeration with FACSCount and Guava PCA [corrected].
abstract: OBJECTIVE
  In all CD4+/CD8+ T-cell estimation systems, the reagents used are liquid in nature and have to be transported and stored at 2°-8°C. This causes problems in countries where the ambient temperature is high for most parts of the year or where the laboratories are at remote places.
  
  
  METHODS
  We evaluated a dry format of CD4/CD8 reagents from ReaMetrix (Bangalore, India) against the existing liquid reagents from Becton Dickinson (San Jose, CA, USA) and Guava PCA system (Guava Technologies, Hayward, CA, USA). Blood samples collected during March 2009 through May 2009 from 102 HIV-infected individuals and 31 normal healthy individuals in a tertiary care centre in India (south) were tested by Guava EasyCD4 System (PCA) and FACSCount using the respective reagents and the corresponding ReaMetrix reagents.
  
  
  RESULTS
  Overall, the correlation (r) of the new Rea T Count and FACSCount reagents for the CD4+ T-cell estimation was 0.98, while with ReaPan 3 4 G reagent in the Guava PCA system with the Guava reagent was 0.97. The mean bias for CD4+ T-cell measurements between Rea T count and BD reagent was -6 cells/ml, while the same with ReaPan 3 4 G reagent in the Guava PCA system was 78 cells/ml. The mean bias for the Rea T count and the ReaPan 3 4 G reagent tested in the FACSCount and Guava PCA system was 17 cells.
  
  
  CONCLUSIONS
  The dry reagents were found to be reliable and cheaper compared to the existing liquid reagents. This allows the transportation of reagents in the absence of cold chain and will facilitate a more user-friendly CD4+ T-cell testing system.
authors: Department of Clinical Virology, Christian Medical College, Vellore   632 004, India.
authors: J
authors: J
authors: Sachithanandham
authors: K
authors: K
authors: Solomon
authors: S
authors: S
authors: Prasannakumar
authors: G
authors: G
authors: Nithyandham
authors: R
authors: R
authors: Kannangai
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D015658:HIV Infections / Q000276:immunology; D006801:Humans; D007194:India; D018655:Lymphocyte Count / Q000379:methods*; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D000091402:Prohibitins