A common principle to ameliorate underquantification because

A common principle to ameliorate underquantification because of primer or probe mismatching is to employ multiple targets for detection or quantification of blood borne viruses [14]. Dual targeting real time PCRs have become common for quantification of HIV-1 [15], [16]. In a recent paper arguing for the necessity of dual targeting also for the quantification of HBV DNA, cloned HBV sequences were shown to be underquantified by the CAPCTMv2 test [17]. The Aptima HBV assay is the first commercially available test for the quantification of HBV DNA to employ dual targeting. The precise algorithm for quantifying HBV DNA based on the two regions amplified is currently not within the public domain, however, the Aptima HIV Quant Dx assay uses a primary target, pol, for quantification, and the secondary target, LTR, is only used if amplification of the primary target fails [18] Further studies will be needed to demonstrate if dual targeting has improved robustness of quantification by the assay. We found both tests sensitive and precise. It is a limitation of the study that the dilutions series were not sufficiently extended to fully assess LOD. The two assays are tightly correlated and will agree in classification of most samples to clinical decision thresholds of 2000 and 20,000 IU/mL. The agreement between the two tests at these thresholds seems comparable to what was recently reported between different generations of COBAS tests for quantification of HBV DNA [19]. In conclusion, we find both tests valuable for clinical monitoring of individuals with chronic HBV infection.
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Background Hepatitis B virus (HBV) infection is a major public health problem worldwide. Individuals with chronic HBV infection are at risk for cirrhosis, liver failure, and hepatocellular carcinoma. Treatment against HBV aims to maintain undetectable HBV DNA levels and to improve the prognosis of HBV-related liver disease. Despite advances in vaccination and treatment, the global burden of HBV remains high. Approximately 30% of the world's Canine HGF / Hepatocyte Growth Factor Protein shows serological evidence of a current or past HBV infection, and an estimated 257 million people were living with chronic HBV infection globally in 2015 [1,2]. The presence of HBV DNA in the blood reflects virus replication and the course of chronic infection [3]. Thus, detection of the HBV DNA level is important for the diagnosis of HBV infection, therapy initiation, monitoring resistance to therapy, and establishing treatment success [1,4]. Most HBV DNA assays that are currently in use are real-time PCR assays [1]. Real-time PCR assays have better analytical sensitivity, specificity, accuracy, and a dynamic range of linear quantification than other technologies [5]. Several commercially available assays based on real-time PCR are fully or partly automated. The COBAS AmpliPrep/COBAS TaqMan HBV, version 2.0 (CAP/CTM v2.0; Roche Molecular Systems, Pleasanton, CA, USA) and Abbott RealTime HBV assay (Abbott Molecular, De Plaines, IL, USA) are the most widely used tools for HBV DNA quantification. The cobas HBV test (Roche Molecular Systems) is a newly developed assay for HBV DNA quantification and accompanies the cobas® 4800/6800/8800 system (Roche Molecular Systems). The Cobas HBV test and CAP/CTM v2.0 are both based on fully automated nucleic acid extraction and real-time PCR, but the Cobas HBV test has a broader range of quantification and a lower limit of detection with a low turnaround time than the CAP/CTM v2.0 according to the manufacturer.
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Methods
Results
Discussion The HBV DNA concentrations in the blood can vary from undetectable to more than 109 IU/mL during the course of chronic HBV infection. To address clinical needs, sensitive nucleic acid amplification technologies are recommended for quantification of the HBV load. To the best of our knowledge, this study is the first to evaluate the performance of the cobas HBV test using the cobas 4800 system and to compare the HBV DNA quantification ability of the cobas HBV test with that of the CAP/CTM v2.0 assay using plasma samples. Because CAP/CTM v2.0 has been predominantly used in routine diagnostic laboratory tests, these comparison data are clinically meaningful.