molecualr diagnostics ,comparison with roche hbv kit
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Evaluation of a Novel Domestic Hepatitis B Viral DNA QuantitativeFluorescence Diagnostic Kit
SHEN Tao1, LONG Lu1, DENG Zhong-ping2, Wang Jie1, DAI Li- zhong2, CHEN De-xi3, TAN De-ming4,
ZHUANG Hui1 and LU Feng-min1*
Department of Pathogen Biology, School of Basic Medicine, (former Infectious Diseases Research Center),
Peking University, Beijing, P. R. China1; Sansure Biotech Inc. Changsha, Hunan Province, P. R. China 2; Beijing
YouAn Hospital, Capital Medical University, Beijing, P. R. China 3; XiangYa Hospital, Central South University,
Changsha, Hunan Province, P. R. China4
*Correspondeing author, E-mail: lufengmin@hsc.pku.edu.cn
Chin J Lab Med, 2013,36:280-285【Abstract】Objective A comparative study was performed between a novel domestic HBV DNA
quantitative fluorescence diagnostic kit (Sansure) and its counterpart Roche Cobas Ampliprep/COBAS
Taqman HBV test kit in order to assess their performance characteristics. Methods Firstly, WHO
international standard for HBV-DNA was diluted to 50, 200, 2000, 20 000 IU/ml separately, and then all
diluted samples were detected by both the novel domestic HBV DNA quantitative fluorescence diagnostic
kit and Roche Cobas Ampliprep/COBAS Taqman HBV test kit to perform traceability analysis and to
determine kits’ reliability. Secondly, pre-diluted series of standard HBV B and C genotype plasma (25, 50,
200, 2000, 20 000, 200 000 IU/ml) were simultaneously performed 216 times for three-center detection by
use of the domestic and Roche HBV DNA test kits separately. Accuracy and precision of those two types of
HBV DNA kits were comparatively analyzed. Finally, a total of 42 clinical plasma samples including 5
negative HBV DNA and different concentration levels of 37 positive HBV DNA were detected by the above
two types of kits to perform clinical quality evaluation. Results Traceability results showed that both
HBV DNA test kits agreed with the HBV DNA WHO standard across all four titers tested and all absolute
differences (observed mean HBV HBV-expected HBV DNA) were within 0.3 log IU/ml. Accuracy results
indicated that the deviation of all observed values at 6 titers (both of HBV genotyping B and C) tested were
within the acceptance criteria (0.005-0.280 lg IU/ml). Comparative performance of coefficient of variation of
PCR assays to HBV genotypes B and C measured by both kits showed that there were no differences of
precision found ( genotyping B: t = 1.226, P = 0.275; genotyping C: t = 2.319, P = 0.07). The clinical
performance of the domestic assay compared to the COBAS assay had been assessed on a panel of 42
clinical specimens. The qualitative results indicated that the total concordant results between two tests were
determined in 97.62% (41/42) of samples. Also, a significant correlation was observed between values tested
by two HBV DNA kits(R2= 0.934, P < 0.0001). Conclusion No significant differences of the traceability,
accuracy, precision and clinical detection are found between two kits. (Chin J Lab Med, 2013,36:280-285)
【Key words】Hepatitis B virus; DNA, viral; Reagent kits, diagnostic; Evaluation studies
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This research was funded by the following projects: (1) Research on Hepatitis B and C Diagnosis and
Clinical Monitoring, “12th Five-year Plan” special project, the Prevention and Treatment of Major Infectious
Diseases Including AIDS and Viral Hepatitis (2012ZX10002005); (2) the “863 Project”, Highly Sensitive
Test Kits and Genome-Based Diagnostic and Therapeutic Technology, the “12th five-year plan” of the
National Ministry of Science and Technology(2012AA022605).
HBV infection is one of the major causes of cirrhosis and hepatocellular carcinoma.[1-2] The HBV DNA
present in HBV-infected human plasma (serum)is an important indicator for understanding HBV replication
in liver, diagnosing HBV infection, monitoring efficacy and providing proper treatment. Recently,
although domestic quantitative test kits for HBV DNA detection have been dramatically improved,
compared to imported test kits, a wide gap still exists in terms of sensitivity, accuracy and reproducibility,.
Major international HBV DNA quantitative test kits such as those made by Roche have a detection limit of
12-20 IU/ml; while main domestic HBV DNA quantitative test kits mostly based on a boiling method for
nucleic acid extraction have a detection limit in the range of 500 - 1000 IU/ml and cannot meet the needs of
clinical diagnostic. With the support from national projects for prevention and control of infectious diseases
included in the 11th and 12th Five-Year Plans, domestic HBV DNA quantitative test kits based on
magnetic-bead method for nucleic acid extraction have got mainstream research support. In this study, we
evaluated the novel HBV DNA quantitative fluorescence diagnostic kit from the Sansure Biotech Inc.
(hereinafter referred as “novel quantitative test kit”) in the aspects of traceability, accuracy, precision and
clinical quality. The evaluation samples included WHO HBV DNA standard, standard HBV B genotype
plasma from the Clinical Laboratory Center of the Ministry of Health of China , standard HBV C genotype
plasma from National Institutes for Food and Drug Control, and the clinical serum panel established by our
laboratory for HBV DNA quantitative test kit evaluation during the 11th Five-Year Plan.
Materials and MethodsMaterialsWHO HBV DNA standard (genotype A2)
TheWHO standard for HBV DNA quantification (code 10/264) was purchased from the National
Institute for Biological Standards and Control (NIBSC). The standard has HBV concentration of 850 000
IU/ml,and 0.5 ml, stored at -70℃. It is re-suspended with sterilized double distilled DNA-free water at 4℃
before use. This WHO HBV standard was diluted to 50, 200, 2000 and 20 000 IU/ml (4 key concentrations
in HBV antiviral treatment) separately with HBV-negative plasma containing EDTA anticoagulant.
Standard HBV B genotype plasma
The HBV B standard with catalog number GBW09150 was provided by the Clinical Laboratory Center
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of theMinistry of Health at no cost with concentration at 1.2×106 IU/ml, stored at -70℃. It was re-thawed by
sterilized double distilled DNA-free water at 4℃ before use. A 0.25 ml of re-suspended standard was added
to 14.75 ml of negative plasma and mixed to achieve 20 000 IU/ml. The standard plasma was further diluted
with negative plasma to make 25, 50, 200, 2000, 20 000, 200 000 IU/ml HBV B plasma.
Standard HBV C genotype plasma
The HBV C standard of with concentration at 2×108 IU/ml was provided by the National Institutes for
Food and Drug Control at no cost and stored at -70℃. After suspended with sterilized water, 0.1 ml of
standard was added to 0.9 ml negative plasma and mixed to achieve 2×107 IU/ml HBV C genotype plasma.
The standard plasma was further diluted with negative plasma to achieve 25, 50, 200, 2000, 20 000, 200 000
IU/ml HBV C plasma.
Negative plasma for dilution
The negative plasma was both HBsAg and anti-HBc negative, and contained EDTA anticoagulant.
Clinical serum panel
Total 42 clinical serum samples were tested, which included 5 HBV DNA negative serum samples
(HBsAg and anti-HBc negative) and 37 HBV DNA positive serum samples (detected positive by Abbott
RealTime HBV Test) with different HBV titers. This serum panel was established by our laboratory for HBV
DNA quantitative test kit evaluation during the 11th Five-Year Plan.
Roche quantitative test kit
Roche COBAS AmpliPrep device and Roche HBV DNA test kit were used to process samples
automatically. COBAS Taqman 48 device was used to automatically amplify and detect nucleic acid. The
Roche quantitative test kit has a detection limit of 16.4 IU/ml for HBV DNA detection. Threshold setting: if
the threshold cycle (Ct) is greater than the upper limit of detection or Ct value is not detected, then it is HBV
DNA negative; if detected < 20 IU/ml, it is HBV DNA positive and < 20 IU/ml; if detected ≥ 20 IU/ml
and ≤ 1.7 ×108 IU/ml, it’s in the detection linear range; if it is detected ≥1.7×108 IU/ml , the sample needs
to be diluted further until it falls in the linear range.
The novel quantitative test kit
With the novel Sansure HBV test kit, HBV DNA in serum samples was extracted with automatic
nucleic acid extraction platform using magnetic-bead technology and quantified using fluorescence
quantitative PCR device. HBV DNA internal control with HEX-labeled TaqMan probe was used to monitor
the presence of PCR inhibitors in samples to prevent false negative results. UNG + dUTP
contamination-proof system was used to avoid a false positive result. The ROX (passive reference) dye was
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also used in the kit to eliminate variations among tubes to ensure accuracy of quantification. For samples
detected between 20 IU/ml and 2.0×109 IU/ml, the copy number results are reported directly. For samples
detected > 2×109 IU/ml, it is reported as > 2.0×109 IU/ml. If more accurate quantification is required, the
sample needs to be diluted 1000 times and tested again. For samples detected ≥10 IU/ml and <20 IU/ml, if
internal control is also detected positive with Ct≤40, it indicates a low viral load and the result is for
reference only. For samples detected < 10 IU/ml with positive internal control (Ct≤40) , it’s reported that
HBV DNA is lower than the detection limit of the quantitative test kit..
MethodsTraceability evaluation
The WHO HBV DNA standard was used to evaluate the traceability of the novel quantitative test kit
and Roche HBV DNA test kit. WHO standard was diluted with HBV negative plasma to 50, 200, 2000 and
20 000 IU/ml, which are the 4 key concentrations for HBV antiviral treatment. One reaction of each diluted
sample was tested on one device each day (including negative control tubes). All diluted samples were tested
total 3 times for each concentration in 3 days.
Accuracy and precision evaluation
HBV negative plasma was used to dilute standard plasma with HBV B and C genotype to 25, 50, 200,
2000, 20 000 and 200 000 IU/ml. One reaction of the 6 diluted samples was tested on one device each day.
All diluted samples were tested total 3 times for each concentration in 3 days. These tests were conducted at
three different test centers, including the Department of Microbiology of Peking University, Beijing Youan
Hospital of Capital Medical University and Xiangya Hospital of Central South University,to evaluate the
accuracy and precision of the two test kits. The accuracy was evaluated according to the relative deviation at
all detection points (the mean logarithmic value of detected value - the logarithm of theoretical value) which
should be within the accepted range of ± 0.3 log10 IU/ml. The precision was evaluated according to the
coefficient of variation (CV) from 9 parallel detections at the same detection point. The less the CV is, the
more precise it is.
Clinical serum panel evaluation
Roche HBV DNA test kit and the novel quantitative test kit were used to test the clinical serum panel to
evaluate the concordance and correlation between the two kits.
Sequencing and evolutionary tree analysis
With the Sansure HBV quantitative test kit, magnetic-bead technology was used to extract HBV DNA
in plasma and nested PCR was used to amplify HBV genomic fragment. The sequence of the outer forward
primer is: 5’-GCTTTGGGGCATGGACATTGACCCGTATAA- 3’, and the outer reverse primer is
5’-CTGACTACTAATTCCCTGGATGCTGGGTCT-3’. The sequence of the inner foward primer is
5’-GACGAATTCCATTGACCCGTATAAAGAATT-3’, and the inner reverse primer is 5’ - ATGGGA
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TCCCTGGATGCTGGGTCTTCCAAA-3’. The evolutionary tree was analyzed using the MEGA5 software.
Neighbor-jioning method and Kimura method were used to build model. Bootstrap was used to repeat the
verification 1000 times. The HBV sequences of different genotypes from GenBank were used as standards,
including HB-J1444AF for genotype A;, AH2 for genotype B; HCC-2-NY, TRF08111, MRK89073 and
NAB1 for genotype C; GRS08457 for genotype D;, HB-J1411F for genotype E;, HBV - BL592 for genotype
F;, HB-J1444GF for genotype G;, and MEX912M for genotype H.
Statistical Analysis
Graphpad prism was used for statistical analysis. The mean value of measurement data, variance,
standard deviation and CV are verified by the use of non-parametric and paired-t tests. The correlation
between the two kits was analyzed using Spearman rank correlation coefficient test. If P <0. 05, the
difference is statistically significant.
ResultsTraceability Analysis Results
In Table 1, it is shown that when using the novel quantitative test kit and Roche quantitative test kit to
test WHO HBV DNA diluted standards, the difference between the detected log10 value at the 4 detection
points of 50, 200, 2 000 and 20 000 IU/ml and the theoretical log value of WHO HBV DNA standard is
within ± 0.3 log10IU/mL (from -0.121 to -0.271 log10IU/ml). This shows that the difference in traceability
between the two diagnostic kits is not statistically significant (t = 0.8639,P > 0.05).
Table 1 Traceability Analysis of the WHO HBV DNA Standard measured by the 2 HBV DNAQuantitative Test Kits
Note: (log10 (detected value) - log10 (theoretical value)) < ±0.3 lg IU/ml is within accepted range.
Accuracy Analysis
The novel quantitative test kit (Sansure) and Roche quantitative test kit were used to test standard
plasma in order to evaluate the two kits' accuracy. As shown in Table 2: for standard genotype B and C
Name of test kitTheoretical value(IU/ml)
Theoreticalvalue(log10 IU/ml)
Detected value( log10 IU/ml)
Relativedeviation( log10 IU/ml)
Standarddeviation( log10IU/ml)
The novel quantitative testkit (Sansure)
50 1.699 1.524 -0.176 0.207
200 2.301 2.119 -0.182 0.205
2000 3.301 3.126 -0.175 0.095
20 000 4.301 4.145 -0.156 0.103
Roche quantitative test kit
50 1.699 1.579 -0.121 0.029
200 2.301 2.056 -0.245 0.092
2 000 3.301 3.030 -0.271 0.131
20 000 4.301 4.135 -0.166 0.202
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plasma, the relative deviation (mean value of detected value - theoretical value) of all detection points
between the two kits was within ±0.3 log10 (IU/ml) (0.005 - 0.28 log10 IU/ml), see Figure 1. This suggested
that the test results of the novel quantitative test kit were very stable with a relative deviation within ± 0.1
log10 IU/mL. Although Roche quantitative test kit’s test results are within the accepted range, the standard
genotype B serum had a relative deviation essentially within 0.2 - 0.3 log10 IU/ml. For standard genotype C
plasma (Figure 1b), the accuracy of Roche test kit was better than that for standard genotype B plasma
(Figure 1b), but less stable than the novel quantitative test kit.
Figure 1 Relative deviation analysis of standard HBV genotype B and C plasma samples measured with
Roche and Sansure HBV test kits.
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Table 2 Accuracy and precision analysis of the standard HBV genotype B and C plasma measured with two test kits
HBVgenotype
Test kits to beevaluated
Theoreticalvalue(IU/ml)
Theoreticalvalue(log10IU/ml)
Testtimes
(log10IU/ml)Detectedvalue
Detectedvalue(IU/ml)
Relativedeviation(log10 IU/ml)
Variance (standarddifference)(log10 IU/ml)
LognormalCV%
HBVgenotypeB
Sansure HBVDNA Test Kit(PCR-Fluorescen-ce Probing)
25 1.398 9 1.362 23.7 -0.036 0.013 (0.114) 8.3850 1.699 9 1.704 52.5 0.005 0.017 (0.130) 7.61200 2.301 9 2.341 226 0.04 0.012 (0.110) 4.742000 3.301 9 3.361 2350 0.06 0.009 (0.097) 2.7020 000 4.301 9 4.342 22 600 0.041 0.012 (0.108) 2.49200 000 5.301 9 5.328 216 000 0.027 0.006 (0.079) 1.49
Roche HBVDNA Test Kit(COBAS 2.0)
25 1.398 9 1.642 46.9 0.244 0.027 (0.167) 10.1750 1.699 9 1.945 88.7 0.246 0.003 (0.054) 2.80200 2.301 9 2.491 317 0.19 0.011 (0.106) 4.272000 3.301 9 3.518 3320 0.217 0.003 (0.056) 1.5920 000 4.301 9 4.581 38400 0.28 0.003 (0.059) 1.28200 000 5.301 9 5.398 251000 0.097 0.002 (0.048) 0.89
HBVgenotypeC
Sansure HBVDNA Test Kit(PCR-Fluorescen-ce Probing)
25 1.398 9 1.325 22.8 -0.073 0.027 (0.166) 12.5250 1.699 9 1.693 52.6 -0.006 0.025 (0.157) 9.29200 2.301 9 2.348 237 0.047 0.024 (0.155) 6.582000 3.301 9 3.295 2080 -0.006 0.023 (0.153) 4.5320 000 4.301 9 4.304 20400 0.003 0.006 (0.077) 1.80200 000 5.301 9 5.329 217000 0.028 0.007 (0.083) 1.56
Roche HBVDNA Test Kit(COBAS 2.0)
25 1.398 9 1.540 39 0.142 0.049 (0.222) 14.4150 1.699 9 1.785 64.5 0.086 0.024 (0.156) 8.75200 2.301 9 2.277 206 -0.024 0.035 (0.188) 8.242000 3.301 9 3.351 2380 0.05 0.024 (0.154) 4.6020 000 4.301 9 4.371 25800 0.07 0.035 (0.188) 4.30200 000 5.301 9 5.325 223000 0.024 0.023 (0.152) 2.85
Note: (log10 (detected value) - log10 (theoretical value)) < ± 0.3 lg IU/ml is considered to be within accepted range.
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Figure 2 Comparative CV analysis of standard HBV B (a) and C (b) plasma samples at different HBV-DNA
concentrations
Figure 3 Comparative CV analysis of low viral load (25, 50, 200 IU/ml) and high viral load plasma samples
(2000, 20000, 200000 IU/ml) with HBV B (a) and C(b) genotypes
Precision Analysis Results
The two quantitative test kits were used to detect standard plasma samples of different viral loads with
HBV B and C genotype at different test centers to evaluate the precision of the kits. See Figure 2 for results.
The results showed that the difference of precision between the two kits was not statistically significant
(genotype B: t = 1.226,P > 0.05; genotype C: t = 2.319,P > 0.05) . Meanwhile, the CV of the two test kits
was compared at different detection point. When the two test kits were used to test low viral load plasma
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samples, the CV was significantly higher than high viral load plasma (genotype B: t = 3.863,P = 0.0031;
genotype C: t = 5.067,P = 0.0005), see Figure 3.
Evaluation Results for Clinical Serum Panel
The clinical serum panel was composed of 42 HBV negative plasma samples and HBV positive plasma
samples with different levels of HBV DNA. Roche test kit and the novel test kit (Sansure) were used to test
the 42 clinical samples separately. See Table 3 for results. Among the 42 samples, 41 samples had
concordant results and the concordance rate reached 97.62%. For the 37 positive samples, the results of the
two test kits were significantly correlated (R2= 0.934,P < 0.0001). See Figure 4. Among the samples, two of
them (sample No. 236 and 283) were tested positive by Roche test kit and was < 20 IU/ml. When they were
tested by the novel test kit (Sansure), the results were about 10 IU/ml. For these 2 samples, we designed
primers for nested PCR to amplify a region flanking the target gene region in the novel test kit (Sansure)
with both positive and negative controls. The amplified products were cloned and sequenced (at least 3
clones per sample). The results proved that the sample number 236 and 283 had HBV gene sequence and the
PCR product size was 258 bp which matched the theoretical sequence length. Evolutionary tree analysis was
conducted on the sequencing results with HBV genotypes A-H standard sequences (Figure 5) and showed
both samples were genotype C but belonged to two subtypes.
Table 3 Comparative results of the 42 samples from clinical serum panel tested with Roche and Sansure
HBV DNA test kits
Roche Test Kit The novel test kit
Positive Negative
Positive 37 0
Negative 1 4
Aggregate 38 4
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Figure 4 Correlation of log10 quantitative HBV DNA concentrations of samples from the clinical serumpanel tested with Roche and Sansure HBV test kits. .
Note: HBV standard sequences are HCC-2-NY, TRF08111, MRK89073, NAB1, HB-J1444AF, AH2,
GRS08457, HB-J1411F, HBV-BL592, HB-J1444GF and MEX912M, and corresponding GenBank No. are
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AB113876, AB554015, AB554025, AB644280, AP007263, AB602818, AB554023, AP007262, AB166850,
AP007264 and AB516394.
Figure 5 Evolutionary tree analysis on sequencing results of NO. 236 and 283 samples from the clinical
serum panel.
DiscussionQuantification of HBV DNA is of great significance for the analysis of HBV infection progress,
evaluation of the efficacy of antiviral treatment and drug resistance monitoring [4]. Currently, there are
various domestic HBV DNA quantitative test kits which vary dramatically in sensitivity, linear range, and
precision of low copy sample tests [5-6]. When some chronic hepatitis B patients with antiviral treatment were
tested for HBV, their HBV DNA level was shown to be lower than the detection limit of domestic kits but
can be detected by imported test kits, which indicates the low sensitivity of domestic HBV DNA test kits.[7]
Roche HBV test kit has been internationally recognized as a reference test kit for HBV DNA quantification
with sound sensitivity, accuracy, reproducibility and wide linear range. By comparison, it’s apparent that low
sensitivity and poor reproducibility are caused by poor nucleic acid extraction and purification processes. For
instance, HBV DNA in plasma samples with low viral load are usually difficult to detect and test results can
not reflect the actual level of HBV DNA[5]. By introducing advanced nucleic acid test technologies from
Europe and America, Sansure Biotech Inc. has developed a nucleic acid extraction technology based on
magnetic-bead method and a high-precision nucleic acid quantification system with independent intellectual
rights. The magnetic-bead extraction system is also suitable for automation, which provides a simple
operation with quality being close to or reaching international standard.
In this study, the traceability analysis showed that the concordance of the detected values from both
Sansure and Roche kits and the theoretical values of the WHO standards are very good, with relative
deviations < ± 0.3 log10 IU/ml, which is within the accepted range. The novel test kit from Sansure also
showed high accuracy in testing standard HBV genotypes B and C plasma samples compared to Roche test
kit (relative deviation within ±0.3 log10 IU/ml). However, when testing standard genotype B plasma sample,
the novel test kit (Sansure) showed a better accuracy than Roche test kit. This could be due to that the
primers and probes in the novel test kit are designed mainly to target the domestic HBV epidemic strains
(B/C genotype) in China. For precision analysis, the CV of both Roche and the novel test kit is < 15%, of
which the difference is not statistically significant. However, for both kits, the test CV of the low viral load
samples was higher than high viral load samples, which suggested that they all need to improve the precision
of testing low viral load samples. In clinical serum panel evaluation, the overall concordance of the novel test
kit and Roche test kit reached 97.62%. The two kits were highly correlated (R2= 0.937,P < 0.0001). When
testing low viral load samples, the two kits were essentially the same in performance. One sample showed
discrepant result, which was detected positive by the Sansure HBV test kit with viral load < 10 IU/ml, but
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negative by the Roche HBV test kit. We used both kits to extract nucleic acid separately and repeated
experiment showed both negative results, which indicates the stability of the Sansure HBV test kit needs to
be improved.
Our study did not conduct rigorous evaluation on the linear range of ultra-high viral load clinical
samples ( >2.0×108 IU/ml) because these samples were not collected in ample quantity. Furthermore, Roche
test kit could be stored at 2 - 8℃ for 18 months but the novel test kit (Sansure) could be stored at -20±5℃
for 9 months. The novel test kit (Sansure) should be improved in storage condition and the term of validity.
In summary, the Sansure HBV test kit shows no significant difference from the Roche test kit in terms
of traceability, accuracy and precision. The study proves the high sensitivity and reliability of the Sansure
HBV test kit for HBV DNA quantification. Due to the competitive price, it is worthwhile to promote its use
in large scale clinical application.
Declaration: The novel test kit is an important outcome of the national major projects during the 12th 5-year
plan period. Sansure Biotech Inc. is involved in primer designing, sequencing and evolutionary tree analysis.
This study has no interest relations with Sansure Biotech Inc.
References[1] Lu FM, Zhuang H. Management of hepatitis B in China. Chin Med J (Engl), 2009,122: 3-4.
[2] Franco E, Bagnato B, Marino MG, et al. Hepatitis B: Epidemiology and prevention in developing
countries. World J Hepatol, 2012,4:74-80.
[3] Garson JA, Grant PR, Ayliffe U, et al. Real-time PCR quantitation of hepatitis B virus DNA
using automated sample preparation and murine cytomegalovirus internal control. J Virol
Methods, 2005,126(1-2):207-213.
[4] Hochberger S, Althof D, Gallegos de Schrott R, et al. Fully automated quantitation of Hepatitis B virus
(HBV) DNA in human plasma by the COBAS® AmpliPrep/COBAS® TaqMan® System. J Clin
Virol, 2006,35:373-380.
[5] 蒋素贞,鲁凤民,庄辉. 慢性乙型肝炎病毒 DNA定量检测的临床意义. 中华检验医学
杂志,2012,35: 117-121.
[6] 李美忠,王敏,乐晓华,等.四种 HBV DNA荧光定量 PCR试剂比较及其结果分析. 中
华实验和临床感染病杂志 (电子版), 2008,1:7-12.
[7] 叶剑荣,袁利群,范旭,等.两种 HBV DNA荧光定量试剂盒检测结果比较. 国家检验
医学杂志, 2012, 33:1480-1481.
(Date of receival: December 21, 2012)
(Edited by Li Jian-ling)
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