title: Laboratory and field evaluation of the Partec CyFlow miniPOC for absolute and relative CD4 T-cell enumeration.
abstract: BACKGROUND
  A new CD4 point-of-care instrument, the CyFlow miniPOC, which provides absolute and percentage CD4 T-cells, used for screening and monitoring of HIV-infected patients in resource-limited settings, was introduced recently. We assessed the performance of this novel instrument in a reference laboratory and in a field setting in Senegal.
  
  
  METHODS
  A total of 321 blood samples were obtained from 297 adults and 24 children, all HIV-patients attending university hospitals in Dakar, or health centers in Ziguinchor. Samples were analyzed in parallel on CyFlow miniPOC, FACSCount CD4 and FACSCalibur to assess CyFlow miniPOC precision and accuracy.
  
  
  RESULTS
  At the reference lab, CyFlow miniPOC, compared to FACSCalibur, showed an absolute mean bias of -12.6 cells/mm3 and a corresponding relative mean bias of -2.3% for absolute CD4 counts. For CD4 percentages, the absolute mean bias was -0.1%. Compared to FACSCount CD4, the absolute and relative mean biases were -31.2 cells/mm3 and -4.7%, respectively, for CD4 counts, whereas the absolute mean bias for CD4 percentages was 1.3%. The CyFlow miniPOC was able to classify HIV-patients eligible for ART with a sensitivity of ≥ 95% at the different ART-initiation thresholds (200, 350 and 500 CD4 cells/mm3). In the field lab, the room temperature ranged from 30 to 35°C during the working hours. At those temperatures, the CyFlow miniPOC, compared to FACSCount CD4, had an absolute and relative mean bias of 7.6 cells/mm3 and 2.8%, respectively, for absolute CD4 counts, and an absolute mean bias of 0.4% for CD4 percentages. The CyFlow miniPOC showed sensitivity equal or greater than 94%.
  
  
  CONCLUSIONS
  The CyFlow miniPOC showed high agreement with FACSCalibur and FACSCount CD4. The CyFlow miniPOC provides both reliable absolute CD4 counts and CD4 percentages even under the field conditions, and is suitable for monitoring HIV-infected patients in resource-limited settings.
authors: Immunology unit, Laboratory of Bacteriology Virology, Le Dantec Hospital, Dakar, Senegal; Laboratory of Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
authors: Djibril
authors: D
authors: Wade
authors: Immunology unit, Laboratory of Bacteriology Virology, Le Dantec Hospital, Dakar, Senegal.
authors: Papa Alassane
authors: PA
authors: Diaw
authors: Laboratory of Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors: Géraldine
authors: G
authors: Daneau
authors: Immunology unit, Laboratory of Bacteriology Virology, Le Dantec Hospital, Dakar, Senegal.
authors: Abdoul Aziz
authors: AA
authors: Diallo
authors: Immunology unit, Laboratory of Bacteriology Virology, Le Dantec Hospital, Dakar, Senegal.
authors: Souleymane
authors: S
authors: Mboup
authors: Immunology unit, Laboratory of Bacteriology Virology, Le Dantec Hospital, Dakar, Senegal.
authors: Tandakha Ndiaye
authors: TN
authors: Dieye
authors: Laboratory of Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
authors: Luc
authors: L
authors: Kestens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry / Q000295:instrumentation / Q000379:methods*; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D015203:Reproducibility of Results; D012675:Senegal; D055815:Young Adult