title: Sensitivity of HCV RNA and HIV RNA blood screening assays.
abstract: BACKGROUND
  The FDA requirement for sensitivity of viral NAT methods used in blood screening is a 95-percent detection limit of 100 copies per mL, whereas the NAT screening system should have a sensitivity of at least 5000 copies per mL per individual donation. According to the Common Technical Specifications of the European Directive 98/79/EC for in vitro diagnostics, viral standard dilutions (calibrated against the WHO standard) should be tested at least 24 times for a statistically valid assessment of the 95-percent detection limit.
  
  
  METHODS
  Viral standard dilution panels (PeliCheck, VQC-CLB) were prepared for HCV RNA genotypes 1 and 3 and for HIV RNA genotypes B and E. In a multicenter study, 23 laboratories tested the panels all together in 8 to 91 test runs per NAT method.
  
  
  RESULTS
  The following 95-percent detection limits (and 95% CIs) were found on the HCV RNA genotype 1 reference panels (shown as geq/mL): Gen-Probe TMA, 85 (64-118); AmpliScreen, 126 (83-225); AmpliScreen with NucliSens Extractor, 21 (13-44); Amplicor with NucliSens Extractor, 69 (50-102), and Amplicor with Qiagen extraction technology, 144 (74-102). On HIV RNA genotype B dilution panels, the following 95-percent detection limits were found (shown as geq/mL): Gen-Probe TMA, 31 (20-52); AmpliScreen, 126 (67-311); AmpliScreen with NucliSens Extractor, 37 (23-69), and NucliSens QL assay, 123 (51-566). HIV RNA genotype E panels were detected with equal sensitivity as HIV RNA genotype B panels. In the Gen-Probe TMA assay, the 50-percent detection limits on HIV RNA type B and type E were 3.6 (2.6-5.0) and 3.9 (2.4-5.8) geq per mL, respectively. The HCV RNA genotype 1 and 3 standards were detected with equal sensitivity.
  
  
  CONCLUSIONS
  The differences in sensitivity between NAT assays can be explained by the input of isolated viral nucleic acid in the amplification reactions. The FDA requirements for sensitivity of NAT blood screening assays can be met by the Gen-probe TMA, as well as by the AmpliScreen assays, particularly when combined with the NucliSens Extractor.
authors.affiliation: VQC Laboratory, Sanquin-CLB Diagnostic Division, Amsterdam, The Netherlands.
authors.forename: P Nico
authors.initials: PN
authors.lastname: Lelie
authors.forename: Harry A J
authors.initials: HA
authors.lastname: van Drimmelen
authors.forename: H Theo M
authors.initials: HT
authors.lastname: Cuypers
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Best
authors.forename: Susan L
authors.initials: SL
authors.lastname: Stramer
authors.forename: Catherine
authors.initials: C
authors.lastname: Hyland
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Allain
authors.forename: Pierre
authors.initials: P
authors.lastname: Moncharmont
authors.forename: Christine
authors.initials: C
authors.lastname: Defer
authors.forename: Micha
authors.initials: M
authors.lastname: Nübling
authors.forename: Andreas
authors.initials: A
authors.lastname: Glauser
authors.forename: Marcia
authors.initials: M
authors.lastname: da Silva Cardoso
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Viret
authors.forename: Mervi H
authors.initials: MH
authors.lastname: Lankinen
authors.forename: Lena
authors.initials: L
authors.lastname: Grillner
authors.forename: Urs
authors.initials: U
authors.lastname: Wirthmüller
authors.forename: Joliette
authors.initials: J
authors.lastname: Coste
authors.forename: Volkmar
authors.initials: V
authors.lastname: Schottstedt
authors.forename: Barbara
authors.initials: B
authors.lastname: Masecar
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Dax
mesh_terms: D000327:Adsorption; D001315:Australia; D001331:Automation; D001803:Blood Transfusion / Q000592:standards*; D005060:Europe; D005838:Genotype; D006678:HIV / Q000235:genetics / Q000302:isolation & purification*; D016174:Hepacivirus / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008280:Magnetics; D021141:Nucleic Acid Amplification Techniques; D012367:RNA, Viral / Q000097:blood* / Q000302:isolation & purification; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide; D014158:Transcription, Genetic; D014461:Ultracentrifugation; D014481:United States; D014486:United States Food and Drug Administration; D014766:Viremia / Q000175:diagnosis* / Q000821:virology
chemical_list: D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic; D012822:Silicon Dioxide