Comparison of Transcription-Mediated Amplification and Real-Time PCR Assays for Hepatitis B Virus DNA Quantitation in Serum

Alinity m, a Random-Access System, for Hepatitis B Virus DNA Quantification in Plasma and Whole Blood Collected on Dried Blood Spots

The International Liver Association recommends the use of accurate and sensitive molecular methods for determination of hepatitis B virus (HBV) DNA levels in plasma or serum of chronic HBsAg carriers. The level of HBV replication represents the strongest predictive biomarker associated with disease progression and long-term outcome of chronic HBV infection. The purpose of this study was to evaluate the ability to the new Alinity m System to detect and quantify HBV DNA in plasma and whole blood collected on dried blood spots (DBS). Paired plasma and DBS samples from patients chronically infected with various HBV genotypes were tested in parallel for HBV DNA detection and quantification. There is a linear relationship between HBV DNA levels measured in plasma samples using the Alinity m HBV assay and the Xpert HBV viral load assay, used for comparison. A slight deviation (0.03 ± 0.31 log IU/mL) was observed within the quantitative range. In DBS, HBV DNA levels closely correlated with levels measured in plasma. All patients had detectable and quantifiable HBV DNA by DBS testing, except for one patient with a plasma HBV DNA level above 2,000 IU/mL. In conclusion, the newly developed real-time PCR-based assay Alinity m HBV assay can correctly detect HBV DNA in DBS, especially for patients with blood HBV DNA levels above 2,000 IU/mL, and also accurately quantify HBV DNA in plasma samples.

IMPORTANCE Hepatitis B virus is one of the most prevalent blood-borne viruses affecting the liver and causing acute and chronic hepatitis. Only a small proportion of people with HBV infection are diagnosed. HBV DNA measurement is critical in clinical practice for the diagnosis and treatment decisions of patients requiring antiviral therapy. Dried blood spot (DBS) collection provides a simple, practical, and acceptable alternative to venous blood collection, especially in community settings. We have demonstrated high sensitivity and specificity for HBV DNA detection in DBS compared to plasma samples, especially when using clinically relevant cutoffs of 2,000 and 20,000 IU/mL. Results support the use of DBS in community-based settings.

Simple and Feasible Detection of Hepatitis B Virus via Combination of Multienzyme Isothermal Rapid Amplification and Lateral Flow Dipstick Strip

Hepatitis B virus infection is not only a huge burden in the field of social health but also a major public health problem that affects the lives and health of the people. Simple, rapid, feasible detection of HBV is critical for its prevention and spread, especially in the developing countries with low-resource laboratories. To this end, we combined multienzyme isothermal rapid amplification (MIRA) and lateral flow dipstick (LFD) strip to detect HBV. A pair of primers targeting the conserved region of HBV genome was designed and used in MIRA-LFD assay. Our results found that the entire amplification of MIRA-LFD only takes 10 min at 37°C and the dilution of the amplification products was added in the LFD strip and observed by the naked eye after 10 min. The detection sensitivity of this method can reach 10 pg. The 45 clinical samples were detected by MIRA-LFD and real-time PCR. The accuracy rate of MIRA-LFD was 100%. Therefore, these characteristics of our newly developed MIRA-LFD assay make it particularly useful and suitable for detecting HBV in the resource-limited condition.

Rapid and sensitive detection of hepatitis B virus by lateral flow recombinase polymerase amplification assay

Hepatitis B virus (HBV) infection is a major public health priority. In the present study, a lateral flow strip combined with the recombinase polymerase amplification (LF-RPA) assay was developed and evaluated for rapid HBV detection. A primer/probe pair targeting the conserved region of the HBV genome was designed and applied to the LF-RPA. TheRPA was achieved at the isothermal temperature of 39℃ for 30 min, and the RPA products were detected using the LF test. DNA extraction, RPA reaction and endpoint detection will take about 70 min. The LF-RPA assay could detect HBV at as low as 10 copies/reaction, with no cross-reactions with other common pathogens. The LF-RPA assay was performed on 85 samples. Of these, 36 samples tested HBV positive, whereas 49 were negative. Similar results were obtained using the conventional polymerase chain reaction method. Thus, the newly developed LF-RPA assay can be an improved diagnostic tool for rapid and simple HBV detection.

Biomarkers for hepatitis B virus replication: an overview and a look to the future

INTRODUCTION

Hepatitis B virus (HBV) infection is a major public health issue but there are no powerful drugs to eradicate the virus. HBV markers including HBsAg, HBcrAg, HBV RNA, HBcAb, and HBV DNA are becoming promising biomarkers to reflect the natural phases of chronic HBV infection and predict the outcome of anti-HBV treatment.

AREAS COVERED

The authors summarized the biomarkers of HBV replication and presented the current advances of these biomarkers on predicting the outcome of anti-HBV treatment and identifying the progression of chronic HBV infection.

EXPERT OPINION

HBsAg, HBcrAg, HBV RNA, HBcAb, and HBV DNA are noninvasive and feasible biomarkers for monitoring the process of anti-HBV therapy and predicting the progress of HBV infection. However, there are still no strong biomarkers with high sensitivity and specificity for clinical application. Combination of two or more HBV biomarkers, new technique for measuring HBV cccDNA, and searching novel HBV biomarkers are essential for anti-HBV treatment in the future.

Development of Diagnostic Tests for Detection of SARS-CoV-2

One of the most effective ways to prevent the spread of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is to develop accurate and rapid diagnostic tests. There are a number of molecular, serological, and imaging methods that are used to diagnose this infection in hospitals and clinical settings. The purpose of this review paper is to present the available approaches for detecting SARS-CoV-2 and address the advantages and limitations of each detection method. This work includes studies from recent literature publications along with information from the manufacturer's manuals of commercially available SARS-CoV-2 diagnostic products. Furthermore, supplementary information from the Food & Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and World Health Organization (WHO) is cited. The viral components targeted for virus detection, the principles of each diagnostic technique, and the detection efficiency of each approach are discussed. The potential of using diagnostic tests that were originally developed for previous epidemic viruses is also presented.

A Highly Prevalent Polymorphism in the Core Region Impairs Quantification of Hepatitis B Virus (HBV) by the cobas TaqMan HBV Assay

The high genetic variability of hepatitis B virus (HBV) can impair DNA quantification. Here, we investigate a major underquantification of HBV by the cobas TaqMan HBV assay (CTM; Roche). In France, between 2005 and 2017, HBV DNA was detected in 3,102 blood donations by use of the CTM (95% limit of detection [LOD₉₅], 4.8 IU/ml). HBV strains were sequenced in the S region (LOD₉₅, ∼30 IU/ml). Concordant (n = 120) and discordant (n = 45) samples were identified according to the agreement between the plasma viral load (pVL) determined by the CTM and sequencing; all samples were also quantified using the RealTime HBV assay (RTH; Abbott). The viral signature, cloning, and mutagenesis were used to characterize the polymorphism responsible for CTM misquantification. A CTM-RTH discordance (>1 log IU/ml) was found in 14/45 samples that had low pVLs and were successfully genotyped (pVL^low genoS⁺). PreC/C clones of concordant (C1, C2) and discordant (D1, D2) strains were used to challenge the CTM. Strains D1 and D2 were highly underquantified (42- and 368-fold). In clones, mutating the region corresponding to the CTM reverse primer from a discordant sequence to a concordant sequence restored the levels of quantification to 24% (D1→C1) and 59% (D2→C1) of theoretical levels, while mutating the sequence of a concordant strain to that of a discordant strain led to 78-fold (C1→D1) and 146-fold (C1→D2) decreases in quantification. Moreover, mutating positions 1961 and 1962 was enough to induce a 5-fold underquantification. We conclude that the CTM underestimates pVLs for HBV strains with mutations in the reverse primer target. Specifically, the polymorphism at nucleotides 1961 and 1962 is naturally present in 4.79 and 4.22% of genotype A and D strains, which are highly frequent in Europe, leading to a 5-fold decrease in quantification. Quantification using the new-generation Roche C4800 assay is not affected by this polymorphism.

HBV-RNA Co-amplification May Influence HBV DNA Viral Load Determination

Despite effective hepatitis B virus (HBV)‐DNA suppression, HBV RNA can circulate in patients receiving nucleoside/nucleotide analogues (NAs). Current assays quantify HBV DNA by either real‐time polymerase chain reaction (PCR), which uses DNA polymerase, or transcription‐mediated amplification, which uses reverse‐transcriptase (RT) and RNA polymerase. We assessed the effect of RT capability on HBV‐DNA quantification in samples from three cohorts, including patients with quantified HBV RNA. We compared the HBV‐DNA levels by real‐time PCR (cobas HBV, Roche 6800/8800; Xpert HBV, Cepheid), transcription‐mediated amplification (Aptima HBV, Hologic), and real‐time PCR with added RT capability (cobas HBV+RT). In the first cohort (n = 45) followed over 192 weeks of NA therapy, on‐treatment HBV‐DNA levels were higher with cobas HBV+RT than cobas HBV (mean difference: 0.14 log₁₀ IU/mL). In a second cohort (n = 50) followed over 96 weeks of NA therapy, HBV‐DNA viral load was significantly higher with the cobas HBV+RT and Aptima HBV compared with the cobas HBV test at all time points after initiation of NA therapy (mean difference: 0.65‐1.16 log₁₀ IU/mL). A clinically significant difference was not detected between the assays at baseline. In a third cohort (n = 53), after a median of 2.2 years of NA therapy, we detected HBV RNA (median 5.6 log₁₀ copies/mL) in 23 patients (43.4%). Median HBV‐DNA levels by Aptima HBV were 2.4 versus less than 1 log₁₀ IU/mL in samples with HBV RNA and without HBV RNA, respectively (P = 0.0006). In treated patients with HBV RNA, Aptima HBV measured higher HBV‐DNA levels than Xpert HBV and cobas HBV. Conclusion: Tests including an RT step may overestimate HBV DNA, particularly in samples with low viral loads as a result of NA therapy. This overestimation is likely due to amplification of HBV RNA and may have an impact on clinical decisions.