Sensitivity of HCV RNA and HIV RNA blood screening assays.
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.
Lelie
P Nico
PN
VQC Laboratory, Sanquin-CLB Diagnostic Division, Amsterdam, The Netherlands.
van Drimmelen
Harry A J
HA
Cuypers
H Theo M
HT
Best
Susan J
SJ
Stramer
Susan L
SL
Hyland
Catherine
C
Allain
Jean-Pierre
JP
Moncharmont
Pierre
P
Defer
Christine
C
Nübling
Micha
M
Glauser
Andreas
A
da Silva Cardoso
Marcia
M
Viret
Jean-François
JF
Lankinen
Mervi H
MH
Grillner
Lena
L
Wirthmüller
Urs
U
Coste
Joliette
J
Schottstedt
Volkmar
V
Masecar
Barbara
B
Dax
Elizabeth M
EM
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
D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic; D012822:Silicon Dioxide