title: Reliable and accurate CD4+ T cell count and percent by the portable flow cytometer CyFlow MiniPOC and "CD4 Easy Count Kit-Dry", as revealed by the comparison with the gold standard dual platform technology.
abstract: BACKGROUND
  An accurate and affordable CD4+ T cells count is an essential tool in the fight against HIV/AIDS. Flow cytometry (FCM) is the "gold standard" for counting such cells, but this technique is expensive and requires sophisticated equipment, temperature-sensitive monoclonal antibodies (mAbs) and trained personnel. The lack of access to technical support and quality assurance programs thus limits the use of FCM in resource-constrained countries. We have tested the accuracy, the precision and the carry-over contamination of Partec CyFlow MiniPOC, a portable and economically affordable flow cytometer designed for CD4+ count and percentage, used along with the "CD4% Count Kit-Dry".
  
  
  METHODS
  Venous blood from 59 adult HIV+ patients (age: 25-58 years; 43 males and 16 females) was collected and stained with the "MiniPOC CD4% Count Kit-Dry". CD4+ count and percentage were then determined in triplicate by the CyFlow MiniPOC. In parallel, CD4 count was performed using mAbs and a CyFlow Counter, or by a dual platform system (from Beckman Coulter) based upon Cytomic FC500 ("Cytostat tetrachrome kit" for mAbs) and Coulter HmX Hematology Analyzer (for absolute cell count).
  
  
  RESULTS
  The accuracy of CyFlow MiniPOC against Cytomic FC500 showed a correlation coefficient (CC) of 0.98 and 0.97 for CD4+ count and percentage, respectively. The accuracy of CyFlow MiniPOC against CyFlow Counter showed a CC of 0.99 and 0.99 for CD4 T cell count and percentage, respectively. CyFlow MiniPOC showed an excellent repeatability: CD4+ cell count and percentage were analyzed on two instruments, with an intra-assay precision below ± 5% deviation. Finally, there was no carry-over contamination for samples at all CD4 values, regardless of their position in the sequence of analysis.
  
  
  CONCLUSIONS
  The cost-effective CyFlow MiniPOC produces rapid, reliable and accurate results that are fully comparable with those from highly expensive dual platform systems.
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Nasi
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: De Biasi
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Bianchini
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy.
authors.forename: Lara
authors.initials: L
authors.lastname: Gibellini
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Pinti
authors.affiliation: Department of Clinical Pathology, BLU Laboratory, Nuovo Ospedale Civile Sant'Agostino Estense-NOCSAE, Baggiovara, Modena, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Scacchetti
authors.affiliation: Department of Clinical Pathology, BLU Laboratory, Nuovo Ospedale Civile Sant'Agostino Estense-NOCSAE, Baggiovara, Modena, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Trenti
authors.affiliation: Infectious Diseases Clinics, Azienda Ospedaliero-Universitaria Policlinico, via del Pozzo 71, 41124 Modena, Italy.
authors.forename: Vanni
authors.initials: V
authors.lastname: Borghi
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy; Infectious Diseases Clinics, Azienda Ospedaliero-Universitaria Policlinico, via del Pozzo 71, 41124 Modena, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Mussini
authors.affiliation: Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia School of Medicine, via Campi 287, 41125 Modena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cossarizza
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count / Q000191:economics / Q000295:instrumentation*; D005260:Female; D005434:Flow Cytometry / Q000191:economics / Q000295:instrumentation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D012015:Reference Standards; D015203:Reproducibility of Results