title: Comparison of the analytical and operational performance of two viral nucleic acid test blood screening systems: Procleix Tigris and cobas s 201.
abstract: BACKGROUND
  The operational and analytical performance of two automated triplex hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) nucleic acid test (NAT) systems were compared in four screening laboratories of the French Blood Service.
  
  
  METHODS
  Two laboratories evaluated the Procleix Tigris system (Chiron/Gen-Probe) in individual donation (ID) format and two sites used the cobas s 201 system (Roche Molecular Systems) on minipools (MPs) of six donations. The analytical sensitivity, the specificity, and operational performance were compared.
  
  
  RESULTS
  The ID to MP-NAT relative sensitivity factors in standard dilution panels of different genotypes varied between 8.7 and 21.9 for HCV RNA, 6.7 and 14.8 for HIV RNA, and 0.71 and 11.6 for HBV DNA. Tigris was 800-fold more sensitive than cobas s 201 (1:6) for a HIV group O sample, but did not detect the HIV-2 sample picked up by cobas s 201 with equal sensitivity as the HIV-1 group M samples. The specificity of both NAT systems after initial screening of 10,520 donations with Tigris and 1444 test pools on s 201 was 99.9 percent for both systems, but reached 100 percent after the repeat and pool resolution test algorithms. A higher throughput of the pool test protocol on cobas s 201 became apparent when the daily workload was more than 400 donations.
  
  
  CONCLUSIONS
  Tigris ID-NAT format was significantly more sensitive than cobas s 201 MP-NAT in detecting HCV RNA and HIV RNA dilution panels, but despite the 1:6 dilution factor in s 201 the difference in sensitivity was not significant for some of the HBV genotype panels. Both NAT systems demonstrated acceptable operational performance, but for routine use further improvement in system reliability is desirable.
authors.affiliation: Etablissement Français du Sang, La Plaine Saint Denis, France. azzedine.assal@efs.sante.fr
authors.forename: Azzedine
authors.initials: A
authors.lastname: Assal
authors.forename: Valérie
authors.initials: V
authors.lastname: Barlet
authors.forename: Marie
authors.initials: M
authors.lastname: Deschaseaux
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dupont
authors.forename: Pierre
authors.initials: P
authors.lastname: Gallian
authors.forename: Cathy
authors.initials: C
authors.lastname: Guitton
authors.forename: P
authors.initials: P
authors.lastname: Morel
authors.forename: Bernard
authors.initials: B
authors.lastname: David
authors.forename: Philippe
authors.initials: P
authors.lastname: De Micco
mesh_terms: D001331:Automation; D004279:DNA, Viral / Q000097:blood* / Q000235:genetics; D015497:HIV-1 / Q000235:genetics*; D016174:Hepacivirus / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D012367:RNA, Viral / Q000097:blood* / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral