Journal of Clinical Virology - Volume 82 - Supplement 1 - September 2016

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S74 Abstracts / Journal of Clinical Virology 82S (2016) S1–S142
10.2% MSW and 16.2% TSW. All rapid antibody tests were neg-
ative. Among the 653 DBS collected (59 individuals were tested
2–3 times), invalid results due to sample collection or nucleic acid
extraction were obtained in 26 cases (3.98%). HCV-positive results
were obtained in five individuals, who were asked to get a con-
firmatory test in venous blood; one did not answer, another was
negative upon DBS retesting (did not wish to have a venipunc-
ture) and the other three viral loads were undetectable. Thus, a
0.64% false-positivity rate was obtained, and confirmed to be due
to unspecific amplification. Focusing on sexual behaviours, 31.8%
reported condomless receptive anal intercourse with non-steady
partners, 41.3% group sex, and 58% the use of recreational drugs
before or during sex. Regarding STIs, 6% were HIV positive, gonor-
rhoea was especially prevalent in MSW (19.1%) and syphilis in both
MSW (20.7%) and TSW (23.9%).
Conclusions: HCV testing was easily implemented and well
accepted. Data suggests that regular HCV screening of HIV-negative
MSM is not justified. Nevertheless, given the observed high-risk
behaviours and the presence of other STIs, HCV spread amongMSM,
MSW and TSW should be closely monitored. The molecular assay
showed a good performance in DBS, although a small number of
false-positive results was obtained in line with the very low HCV
prevalence observed. This assay is currently being evaluated in
higher prevalence groups, such as injection drug users.
Abstract no: 260
Presentation at ESCV 2016: Poster 107
Clinical evaluation of the Aptima HBV Quant
assay for hepatitis B virus DNA quantification
on Panther system
Heiko Petersen ∗, Joerg Petersen
1 Laboratory Dr. Fenner and Colleagues, Germany
2 ifi-Institute for Interdisciplinary Medicine,
Germany
Background: The Hologic Aptima HBV Quant assay (Aptima
HBV) is a new real-time transcription-mediated amplification
method for use inmonitoring of HBV infection that runs on the fully
automatedPanther systemin randomaccess. Herewe describe vali-
dation studies of the assay compared to the Cobas AmpliPrep/Cobas
TaqMan HBV Quantitative Test, v2.0 (Roche HBV) in a clinical rou-
tine setting.
Methods: For method comparison 387 prospective (274) and
retrospective (113) clinical plasma samples from HBV infected
patients were tested side-by-side in Aptima HBV and Roche HBV
to analyze concordance on qualitative results as well as corre-
lation between quantitative results. Precision was demonstrated
by testing plasma dilutions of the AcroMetrix HBV High Control
(#960603, Thermo Fisher Scientific) in 3 different target concen-
trations, 500, 100, and 25 IU/ml, and tested in replicates of 21 each
with the respective assays. Repeatability across different genotypes
was demonstratedwith the 1st WHO International Reference Panel
for Hepatitis B Virus Genotypes for NAAT-Based Assays (PEI code
5086/08), at a nominal target concentration of 1000 IU/ml, in three
replicates for each genotype. Linearity was assessed by prepar-
ing serial dilutions of 4 well characterized clinical samples (GT A,
GT C, GT D, GT E), with six dilution levels and target concentra-
tions at 7 log IU/ml, 6 log IU/ml, 5 log IU/ml, 4 log IU/ml, 3 log IU/ml,
2 log IU/ml. Five replicates of each dilution level were tested side-
by-side in the Aptima and Roche assays over 3 days, respectively.
Accuracy was tested based on a Qnostics HBV Evaluation Panel
(QNCM14-038-HBV).
Results: With prospective clinical samples (n = 274), inter-assay
agreement between Aptima HBV and Roche HBV for qualita-
tive results was substantial (79.9%). The concordance between
results for 123 prospective and 113 retrospective samples with
quantitative results in both assays was very high. Aptima HBV
reported slightly higher values by an average of just 0.02 and
0.03 log10 IU/mL, calculated according to Bland–Altman method,
respectively. Linear regression gave a Pearson r concordance cor-
relation coefficient of 0.96 (P < 0.0001) for prospective samples and
0.98 ( P < 0.0001) for retrospective samples. Both assays showed
excellent linearity (r > 0.99) across four different serial dilutions of
clinical samples representing different genotypes (GT A, C, D, E),
with regression lines nearly parallel to the identity lines for both
assays. Precision was 0.19 log SD or lower across the dilutions lev-
els with the Acrometrix standard and comparable to Roche. The
Aptima HBV demonstrated excellent accuracy in the Qnostics HBV
EQA panel and proper genotype detection based on the PEI GT
panel, with Aptima result differing not greater than ±0.5 log IU/ml
from nominal target values based on Abbott RealTime HBV and the
comparator assay, Roche HBV, respectively.
Conclusion:The Aptima HBV demonstrated excellent precision,
linearity, and accuracy in all genotypes tested. Excellent concord-
ance was observed between Aptima HBV and Roche HBV when
testing clinical samples from patients on therapy. This study has
demonstrated that Aptima HBV meets the necessary requirements
for HBV viral load monitoring in a clinical routine setting.
Abstract no: 261
Presentation at ESCV 2016: Poster 108
Evaluation of a novel assay for hepatitis C virus
genotype 1 subtyping
M. Jiménez ∗, J. Bola˜nos , M.A. Cuesta ,
E. Bascu˜nana , V. Saludes , L. Matas ,
B. Reinhardt , V. Ausina , E. Martró
1 Microbiology Service, Germans Trias i Pujol
University Hospital, Badalona, Spain
2 Microbiology Service, Germans Trias i Pujol
University Hospital, Germans Trias i Pujol Health
Sciences Research Institute (IGTP), Badalona, Spain
3 CIBER en Epidemiología y Salud Pública
(CIBERESP), ISCIII, Madrid, Spain
4 Abbott GmbH & Co. KG, Wiesbaden, Germany
5 CIBER en Enfermedades Respiratorias (CIBERES),
ISCIII, Madrid, Spain
Background: Due to its high genomic variability, accurate HCV
genotyping and genotype 1 subtyping remains challenging as stud-
ies have reported limitations for sequencing, line probe and PCR
commercial assays. In a few cases, the RealTime HCV Genotype II
assay (GT II, Abbott Molecular) does not assign the genotype 1 sub-
types 1a or 1b (based on the NS5B region). Use of a second assay can
further characterize those ambiguous results in order to provide
clinicianswith the required information formaking treatment deci-
sions.
Aim: The performance of the newHCV Genotype Plus RUO assay
(GT Plus, AbbottMolecular)was evaluated in comparisonwith a ref-
erence method (sequencing and phylogenetic analysis of the NS5B
and core regions) in a set of specimens previously tested by the GT
II assay.
Methodology: The following plasma or extracted RNA speci-
mens previously tested by the GT II assay were studied (n = 66): (i)
45 genotype 1 specimens with no subtype assigned; (ii) 10 spec-