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

76 / 152

S72 Abstracts / Journal of Clinical Virology 82S (2016) S1–S142
we compare the performance of the Hologic Aptima HCV quant
Dx assay (Aptima) to the Roche Cobas TaqMan HCV test, version
2.0, using the high pure system (HPS/CTM), considered a refer-
ence assay since it has been used in trials defining clinical decision
points in patient care. The assays’ performance characteristics were
assessed using HCV RNA reference panels and plasma/serum from
chronically HCV-infected patients. The agreement between the
assays for the 3 reference panels was good, with a difference in
quantitation values of <0.5 log. High concordance was demon-
strated between the assays for 245 clinical sample s (kappa = 0.80;
95% CI: 0.720–0.881); however, Aptima detected and/or quanti-
tated 20 samples that HPS/CTM did not detect, while Aptima did
not detect 1 sample that was quantitated by HPS/CTM. For the 165
samples quantitated by both assays, the values were highly corre-
lated (R = 0.98; P< 0.0001). The linearity of quantitation from 1.4 to
6 log was excellent for both assays for all HCV genotypes tested
(GT 1a, 1b, 2b and 3a) (R2 > 0.99). The assays had similar total and
intra-assay variability across all genotypes from 1000 to 25 IU/mL.
Aptima had a greater analytical sensitivity, quantitating more than
50% of replicates at 25 IU/ml target. Aptima showed performance
characteristics comparable to those of HPS/CTM and increased sen-
sitivity, making it suitable for use as a clinical diagnostic tool on the
fully automated Panther platform.
Abstract no: 24
Presentation at ESCV 2016: Poster 103
Association of rs731236(Taq1)VDR TT genotype,
chronic hepatitis B infection and serum vitamin
D level
M. Atoum ∗, H. Hawmdeh
Hashemite university, Jordan
Aim: The role of vitamin D in chronic hepatitis B (CHB) infection
has attracted a lot attention, the aim of this study is to determine
the association between rs731236(Taq1)VDR TT genotype, serum
circulating 25-hydroxyvitamin D (25 (OH) D) among CHB patients.
Methods: This study enrolled one hundred and twenty nine
CHB patients, one hundred and thirty thee healthy Jordanians as
a control from Prince Hamzah and Al-Basheer Hospitals/Amman
(2013-2015). 25 (OH) D level was determined by competitive
immunoassay, Hepatitis B antigen (HBsAg) was determined by
HBsAg ELISA and rs731236(Taq1)VDR TT genotypewas determined
by polymerase chain reaction.
Results: Mean level of serum 25(OH)D among CHB patients
was significantly lower (11.2 ±15.1) compared to heathy control
(19.3 ± 3.4). The percent of CHB patients with deficient, insuf-
ficient and optimal 25(OH)D was (55.8%, 28.6%, 15.5%) among
CHB compared to (43.6%, 32.3 and 24.1%) among healthy control;
respectively. Statistical difference was found in vitamin D level
within rs731236(Taq1)VDR TT genotype among the CHB patients
(10.6 ± 4.3 ng/mL) compared to its control (20.41± 3.3 ng/mL).
Conclusion: Vitamin D deficiency and rs731236(Taq1)VDR TT
genotype are common among patients with CHB and is may be
associated with adverse CHB clinical outcomes.
Abstract no: 243
Presentation at ESCV 2016: Poster 104
Clinical evaluation of the Aptima HCV Quant Dx
assay for hepatitis C virus RNA quantification on
Panther system
Heiko Petersen ∗, Peter Buggisch
1 Laboratory Dr. Fenner and Colleagues, Germany
2 ifi-Institute for Interdisciplinary Medicine,
Germany
Background: The Hologic Aptima HCV Quant Dx assay (Aptima
HCV) is a new real-time transcription-mediated amplification
method for use in diagnosis and monitoring of HCV infection that
runs on the fully automated Panther system in randomaccess. Here
we describe validation studies of the assay compared to the Cobas
AmpliPrep/Cobas TaqMan HCV Quantitative Test, v2.0 (Roche HCV
Quant) and Cobas AmpliPrep/Cobas TaqMan HCV Qualitative Test,
v2.0 (Roche HCV Qual) in a clinical routine setting.
Methods: For method comparison 543 prospective (438) and
retrospective (105) clinical plasma samples from HCV infected
patients were tested side-by-side in Aptima HCV and Roche HCV
to analyze concordance on qualitative results as well as correla-
tion between quantitative results. Precision was tested using the
PEI HCV-RNA Reference Standard (#3443/04, GT 1) diluted with
negative plasma to 3 different target concentrations, 500, 100, and
25 IU/ml and tested in replicates of 21 each with the respective
assays. Repeatability across different genotypes was demonstrated
with and HCV genotype panel from the German NRC for HCV.
Linearity was assessed by preparing serial dilutions of 4 well char-
acterized clinical samples (GT 1a, GT 1b, GT 3, GT 6), with five
dilution levels and target concentrations at 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. Accuracywas tested based on a current Instand
HCV RNA EQA panel.
Results: With prospective clinical samples (n = 223), inter-assay
agreement between Aptima HCV and Roche HCV Quant for qualita-
tive results was high (92.4%) with Cohen’s kappa statistic equal to
0.79. The inter-assay agreement between Aptima HCV and Roche
HCV Qual for qualitative results was also high (95.8%) with Cohen’s
kappa statistic equal to 0.83. Of the 283 prospective and retrospec-
tive samples with quantitative results in both assays, Aptima HCV
reported slightly higher values by an average of 0.2 log10 IU/mL,
calculated according to Bland–Altman method, with Aptima yield-
ing higher VLs in the upper VL range, and slightly lower VLs in the
lower VL range (<5 log IU/ml). Concordance between assay results
was high with a Pearson r concordance correlation coefficient of
0.98 (P < 0.0001). Both assays showed excellent linearity (r> 0.98)
across different genotypes tested, with regression lines nearly par-
allel to the identity lines for Aptime HCV. Precision was 0.17 and
0.12 log SDor lower across the dilutions levelswith the PEI standard
and NRC HCV genotype panel, respectively, and superior to Roche
HCV (<0.2 and <0.29 log SD, respectively). The Aptima HCV demon-
strated excellent accuracy in the Instand HCV EQA panel.
Conclusion:The Aptima HCV demonstrated excellent precision,
linearity, and accuracy in all genotypes tested. Good concordance
was observed between Aptima HCV and Roche HCV when testing
clinical samples from patients on therapy. This study has demon-
strated that Aptima HCVmeets the necessary requirements for HCV
viral loadmonitoring andHCVdiagnosis in a clinical routine setting.