A Simple and Rapid Test-card Method to Detect Hepatitis B Surface Antigen and Antibody: Potential Application in Young Children and Infants

HCV elimination in a Swiss opioid agonist therapy programme - a cohort study

BACKGROUND

In opioid agonist therapy (OAT) programmes, chronic hepatitis C is highly prevalent and directly observed therapy guarantees optimal adherence. Since 2017, all patients with chronic hepatitis C in Switzerland can be treated with pangenotypic direct-acting antivirals irrespective of liver fibrosis stage. Until the end of 2021, however, prescription was restricted to infectious disease specialists, gastroenterologists and certain addiction specialists. Difficult venous access after long-term intravenous drug use and, in the case of referral to a specialist, difficulties keeping appointments are barriers to HCV diagnosis and treatment.

AIMS

To assess whether minimally invasive point-of-care tests and a "test-and-treat / vaccinate on-site" approach can improve human immunodeficiency virus (HIV) / hepatitis C virus (HCV) screening, HCV treatment uptake and immunity against hepatitis A/B.

METHODS

Since September 2018, an infectious disease specialist and a study nurse performed 4-weekly visits in the OAT programme "HAG" (heroin dispensation of the canton Aargau), offering HIV/HCV antibody rapid testing (20 min) and HCV RNA quantification (GeneXpert®, 60 min) from capillary blood, noninvasive liver fibrosis assessment (Fibroscan®, 5-10 min) and HCV treatment prescription on-site. Recommended venous blood draws for HAV/HBV serology and HAV/HBV vaccinations were performed by the staff of the "HAG". Project performance was assessed by annual cross-sectional chart review.

RESULTS

Of the 128 patients registered in April 2018, 79 (62%) were still present in May 2021. With 72 newly registered, a total of 200 patients could be assessed, of whom 129 (65%) were still present in May 2021. Between April 2018 and May 2021, the proportion ever tested for HIV antibodies increased from 79% (101/128) to 91% (117/129), the proportion ever tested for HCV antibodies from 83% (106/128) to 93% (120/129) and the proportion of those HCV antibody positive ever tested for HCV RNA tested from 89% (47/53) to 98% (56/57). The proportion with adequate HCV management (last HCV antibody test ≤1 year ago, if HCV antibody negative or last HCV RNA test ≤1 year ago, if HCV antibody-positive and RNA-negative) improved from 23% ([15 + 15]/128) to 80% ([55 + 48]/129). Overall, HCV treatment uptake increased from 60% (21/35) to 92% (55/60) and HCV RNA prevalence among the HCV antibody positives decreased from 38% (18/47) to 7% (6/84). Between 2018 and 2021, 19 non-cirrhotic chronic hepatitis C patients were successfully treated on-site (18 sustained virological responses [SVR] 12, 1 SVR4), with excellent adherence (≥93%) and, so far, no reinfection. The proportion with known HAV/HBV serostatus increased from 38%/51% to 64%/76%. Immunity against HAV/HBV improved from 19%/23% to 50%/57%.

CONCLUSION

Capillary blood point-of-care tests and a "test-and-treat / vaccinate on-site" approach remove crucial barriers to diagnosis and treatment, making hepatitis elimination in OAT programmes achievable. A high fluctuation rate requires HIV/HCV/HAV/HBV testing at admission, but also allows more patients to be screened.

Clinical utility of the 'Determine HBsAg' Point-of-Care Test for Diagnosis of Hepatitis B Surface Antigen in Africa

INTRODUCTION

Chronic infection with hepatitis B virus (HBV) is a leading cause of morbidity and death, especially in sub-Saharan Africa (sSSA), where approximately 60 million adults are infected. More than 90% of these patients are unaware of their HBV status.

AREAS COVERED

Scaling-up of HBV screening programs in SSA are essential to increase diagnosis, linkage to care and access to treatment, and will ultimately reduce HBV disease burden to achieve WHO hepatitis elimination targets. Such scale up will rely on inexpensive rapid point-of-care (POC) tests, especially in remote areas where gold standard serological assays are not routinely available. This review discusses the diagnostic performance and clinical utility of the Determine™ (Abbott, USA) hepatitis B surface Antigen (HBsAg) POC test for improving HBV screening in SSA, in light with others available HBsAg rapid tests.

EXPERT OPINION

The Determine™ HBsAg POC test has demonstrated relatively good diagnostic accuracy at the low cost, in the African field and laboratory and should be used for large scale mass screening of HBV infection in Africa.

Electrochemical One-Step Immunoassay Based on Switching Peptides and Pyrolyzed Carbon Electrodes

Switching peptides were designed to bind reversibly to the binding pocket of antibodies (IgG) by interacting with frame regions (FRs). These peptides can be quantitatively released when antigens bind to IgG. As FRs have conserved amino acid sequences, switching peptides can be used as antibodies for different antigens and different source animals. In this study, an electrochemical one-step immunoassay was conducted using switching peptides labeled with ferrocene for the quantitative measurement of analytes. For the effective amperometry of the switching peptides labeled with ferrocene, a pyrolyzed carbon electrode was prepared by pyrolysis of the parylene-C film. The feasibility of the pyrolyzed carbon electrode for the electrochemical one-step immunoassay was determined by analyzing its electrochemical properties, such as its low double-layer capacitance (C_dl), high electron transfer rate (k_app), and wide electrochemical window. In addition, the factors influencing the amperometry of switching peptides labeled with ferrocene were analyzed according to the hydrodynamic radius, the number of intrahydrogen bonds, dipole moments, and diffusion coefficients. Finally, the applicability of the electrochemical one-step immunoassay for the medical diagnosis of the human hepatitis B surface antigen (hHBsAg) was assessed.

Comparative assessment of immunochromatography and ELISA diagnostic tests for HBsAg detection in PCR-confirmed HBV infection

INTRODUCTION AND AIMS

Viral hepatitis, which appears most frequently at birth or during childhood, is a disease whose transmission routes include tears, bile, sexual fluids, sweat, milk, urine, feces, and saliva. The aim of the present study was to analyze the specificity of the immunochromatographic and ELISA diagnostic tests for hepatitis B surface antigen and compare them with PCR testing.

MATERIALS AND METHODS

The study sample was made up of 140 men and 60 women referred to the Urmia Medical University hospital to undergo PCR testing for HBV diagnosis. The ELISA test was performed using the Pioneer Medicine Company kit (Tehran, Iran).

RESULTS

The results of the HBs-Ag rapid test and the ELISA test were compared with the PCR test. The HBs-Ag rapid test had 97% sensitivity and 91% specificity, whereas the ELISA test had 78% sensitivity and 76% specificity.

DISCUSSION AND CONCLUSION

According to our results, the immunochromatographic test was accurate for diagnosing HBs-Ag in blood and the ELISA test had acceptable sensitivity and specificity, compared with PCR testing.

Point-of-Care Tests for Hepatitis B: An Overview

Despite the heavy disease burden posed by hepatitis B, around 90% of people living with hepatitis B are not diagnosed globally. Many of the affected populations still have limited or no access to essential blood tests for hepatitis B. Compared to conventional blood tests which heavily rely on centralised laboratory facilities, point-of-care testing for hepatitis B has the potential to broaden testing access in low-resource settings and to engage hard-to-reach populations. Few hepatitis B point-of-care tests have been ratified for clinical use by international and regional regulatory bodies, and countries have been slow to adopt point-of-care testing into hepatitis B programs. This review presents currently available point-of-care tests for hepatitis B and their roles in the care cascade, reviewing evidence for testing performance, utility, acceptability, costs and cost-effectiveness when integrated into hepatitis B diagnosis and monitoring programs. We further discuss challenges and future directions in aspects of technology, implementation, and regulation when adopting point-of-care testing in hepatitis B programs.

An Automated, Quantitative, and Multiplexed Assay Suitable for Point-of-Care Hepatitis B Virus Diagnostics

Hepatitis B virus (HBV) infection has a global reach with high prevalence in resource-limited areas like China and Africa. HBV patients in these areas have limited access to the currently used, costly HBV assays, which are performed in centralized clinical laboratories using single-plexed assays with bulky and expensive instruments. We aim to overcome these limitations by developing a simple and affordable HBV diagnostic platform to allow for timelier diagnosis and intervention of HBV infection. Using giant magnetoresistive (GMR) biosensor chips, we developed an automated and multiplexed quantitative platform for the measurement of a panel of HBV serology markers, including HBV “e” antigen (HBeAg), HBV surface antigen (HBsAg), and the antibody against HBsAg (anti-HBs). Our assay platform was able to detect each HBV marker with high specificity and sensitivity (with three orders of magnitude in dynamic range for each marker). Blinded analysis of HBV patient sera showed excellent correlation between our multiplexed quantitative HBsAg results and the qualitative results obtained using FDA-approved immunoassays, as well as those obtained using quantitative, single-plexed, enzyme-linked immunosorbent assays (ELISAs). The portable, automated, multiplexed, quantitative HBV serology assay platform we designed shows great promise as a more accessible alternative for HBV screening, diagnosis, and treatment monitoring.

Development of a multiplex immunochromatographic strip test and ultrasensitive electrochemical immunosensor for hepatitis B virus screening

This research proposes two methods for hepatitis B diagnosis including rapid testing and electrochemical assay. For the first method, a multiplex hepatitis B test strip was fabricated to serve as a rapid test for hepatitis B screening. It was developed to simultaneously test three essential serological markers of hepatitis B virus infection including hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (Anti-HBs) and hepatitis B core antibody (Anti-HBc). Gold nanoparticles (GNPs) were used as the signal generator on the test strip. Furthermore, a part of a paper network was incorporated on the strip for the gold-silver enhancement process. This paper network helped in decreasing the analysis time of enhancement and makes the enhancement process easier for rapid testing. The developed test strip was specific for each serological marker. The detection limits of HBsAg, Anti-HBs and Anti-HBc were obtained at 0.5, 0.3 and 0.1 μg mL^-1, respectively. For the second method, electrochemical impedance spectroscopy (EIS) was applied for HBsAg detection. This method was proposed for quantitative hepatitis B detection. Anti-HBs antibodies were immobilized on a carbon screen printed electrode (SPCE) via the N-ethyl-N'-(3-(dimethylamino)propyl)carbo-diimide/N-hydroxy succinimide (EDC/NHS) couple reaction which reacted with the carboxyl group of the BSA cross-linked film on the electrode. The electrode modification process was characterized by EIS. A linear relationship between delta charge transfer resistance (ΔRct) and HBsAg concentration was obtained in the range of 5-3000 ng mL^-1 with a detection limit of 2.1 ng mL^-1. This work is appropriate for quantitative analysis because it is a simple and low-cost method to implement as the SPCE is disposable. Therefore, we hope that this research will be useful to improve hepatitis B detection in the future.

Potential Implications of Detecting HBsAg in Asymptomatic People in an Endemic Community Through Medical Camps

BACKGROUND

In a developing country like India with intermediate level of prevalence of hepatitis B, most of the patients remain undiagnosed as they are asymptomatic. The purpose of the study was to diagnose asymptomatic HBsAg positive patients from the general population and evaluate further the potential clinical implications of IDAHS.

METHODS

Asymptomatic subjects with unknown HBV status were screened free of cost for hepatitis-B surface antigen. Those who tested positive for HBsAg were further tested to identify those who were potential candidates for anti-viral therapy. To explore the relevance of our screening we assessed potential implications of HBsAg detection.

RESULTS

A total of 30,836 patients were screened in medical camps over the period of 7 years. Out of these 704 (2.3%) subjects were found to be positive for HBsAg. Distress of being diagnosed with HBV was expressed by 649 (92%) of the positive subjects. High cost of further testing and antiviral therapy, leading to inability to pursue further management was elicited in 510 (72%) of the positive subjects. HBV DNA was detected in 349 (59%) out of 592 subjects, out of which 236 (67%) had high viral load.

CONCLUSION

Incidental detection of asymptomatic HBsAg positive subjects was seen in 2.3% of subjects. One third of these patients had an actively replicating virus and required antiviral therapy. Financial support was required in 72% of the subjects for further HBV management. Detecting HBsAg in asymptomatic person in an endemic community has considerable health and psycho-economic impact on the individual.

Performance of rapid diagnostic tests for the detection of anti-HBs in various patient populations

BACKGROUND

Rapid diagnostic tests (RDTs) represent an attractive alternative method to conventional diagnosis of hepatitis B virus (HBV) infection.

OBJECTIVE

The aim of the present study was to evaluate the diagnostic performance of commercially available RDTs for the detection of anti-HBs in various patient populations.

STUDY DESIGN

A total of 347 individuals, 198 positive and 149 negative for anti-HBs, were studied.

RESULTS

The specificity of RDT detection of anti-HBs in serum was 98.0%, 96.0% and 97.3% with TOYO® HBsAb Test, QuickProfile™ HBsAb test and QuickProfile™ HBV-3 Panel test, respectively. The diagnostic sensitivity varied between 60.4% and 69.5%. The sensitivity of the three RDTs was markedly better when testing serum samples with an anti-HBs titer higher than 100IU/L, and reached 90% or more for an anti-HBs titer above 150IU/L.

CONCLUSIONS

This performance was disappointing because the assays were not sensitive enough to detect low antibody titers. Thus, these tests require further improvement before they can be widely used in clinical practice.

Poor sensitivity of rapid tests for the detection of antibodies to the hepatitis B virus: implications for field studies

Rapid tests (RTs) can be used as an alternative method for the conventional diagnosis of hepatitis B virus (HBV). This study aims to evaluate antibodies to HBsAg (anti-HBs) and antibodies to HBeAg (anti-HBe) RTs under different Brazilian settings. The following three groups were included: GI: viral hepatitis outpatient services; GII: low resource areas; and GIII: crack users and beauticians. Imuno-rápido anti-HBsAg^™ and Imuno-rápido anti-HBeAg^™ RTs were evaluated and showed specificities greater than 95% in all groups. The sensitivity values to anti-HBs were 50.38%, 51.05% and 46.73% and the sensitivity values to anti-HBe were 76.99%, 10.34% and 11.76% in the GI, GII and GIII groups, respectively. The assays had a low sensitivity and high specificity, which indicated their use for screening in regions endemic for HBV.