HBcrAg Rapid Diagnostic Test Shows Potential in Timely Detection of HBV DNA Concentrations

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Key Takeaways

The HBcrAg-RDT effectively identifies high HBV DNA concentrations, with sensitivity and specificity over 93%, surpassing traditional HBeAg assays.
The test offers same-day results, significantly faster than the median 46-day turnaround for conventional HBV DNA testing.
This rapid diagnostic test is particularly beneficial in resource-limited settings, aiding in the timely identification of pregnant women needing antiviral prophylaxis.
The study involved diverse cohorts from Cambodia, Cameroon, and Burkina Faso, demonstrating the test's broad applicability and potential impact on reducing HBV transmission.

The hepatitis B core-related antigen (HBcrAg) rapid diagnostic test was more timely and showed a stronger sensitivity and specificity compared with other testing methods.

Research published in The Lancet Gastroenterology & Hepatology found that a newly developed hepatitis B core-related antigen (HBcrAg) rapid diagnostic test (RDT) has potential in detecting hepatitis B virus (HBV) DNA concentrations in women who should be prioritized for antiviral prophylaxis. The authors noted their optimism in this method an an alternative for timely identification of pregnant individuals who are at a high risk of transmitting HBV.¹

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Hepatitis B is a viral disease that affects the liver and can lead to severe complications, such as cirrhosis and liver cancer. According to experts, there are over 254 million people living with hepatitis B who can potentially transmit the virus and more than 1.1 million hepatitis B-related deaths every year. In countries with limited resources—notably sub-Saharan African countries and the Asia-Pacific region—chronic HBV infections affect about 4% to 8% of the adult population.²

The virus is transmitted through bodily fluids and secretions, with statistics showing that the most common routes of transmission worldwide are mother-to-child transmission and transmission between children. Effective vaccinations have been available since 1981, but antiviral therapy does not yet definitively cure hepatitis B. Additionally, there are existing tests that are used to assess a person’s risk of transmitting hepatitis B—such as tests that measure viral load—but these are often costly and require specialized laboratory equipment, limiting their accessibility in regions that have limited resources.^1,2

For this study, investigators retrospectively validated the HBcrAg-RDT using stored plasma from pregnant women who were HBsAg-positive in cohort studies conducted in Cambodia and Cameroon. Additionally, finger-prick capillary blood from postpartum mothers at rural health centers in Burkina Faso was prospectively used.¹

The purpose of this study was to estimate the sensitivity and specificity of the HBcrAg-RDT for diagnosing high HBV DNA concentrations (≥ 200,000 IU/mL) using real-time polymerase chain reaction (rtPCR) as the reference. Additionally, the investigators compared the diagnostic performance of the test with conventional HbeAg assays.¹

A total of 1964 plasma samples were available for the analysis (Cambodian cohort: n = 1194; Cameroonian cohort: n = 501; Burkina Faso cohort: n = 269). In the pooled population, the mean age was about 28.1 years, and approximately 20.0% (n = 382) were HBeAg-positive.¹

Overall, the HBcrAg-RDT demonstrated a sensitivity of about 93.1% (95% CI: 90.5%-95.2%) and specificity of 94.3% (93.0%-95.4%). In the Cambodia and Cameroon cohort retrospective laboratory-based analyses, the sensitivity and specificity were about 93.4% (95% CI: 90.7%-95.5%) and 94.4% (95% CI: 92.9%-95.6%), respectively, whereas the samples of HBsAg-positive women from the Burkina Faso cohort had a specificity and sensitivity of about 89.7% (95% CI: 75.8%-97.1%) and 93.9% (95% CI: 90.0%-96.6%).¹

Further, the area under the receiver operating characteristic curve (AUROC) for HBcrAg-RDT (0.937 [95% CI: 0.924-0.950]) in distinguishing high versus low HBV DNA concentrations at the 200,000 IU/mL threshold in the pooled data set was significantly higher than that of HbeAg rapid tests (0.822 [95% CI: 0.798-0.845]; p < .0001) and similar to laboratory-based HbeAg immunoassays (ELISA and chemiluminescence assay: 0.926 [95% CI: 0.897-0.955]; p = .72). In the Burkina Faso cohort, the median turnaround time for HBV DNA testing was about 46 days (IQR: 31-72 days), whereas the HBcrAg-RDT provided same-day results for all participants.¹

"Results show that this new test is highly effective at identifying women with a high viral load and offers significant advantages in speed and ease of use compared to traditional methods, such as PCR. This test can be used to reliably identify pregnant women who should benefit from preventive antiviral treatment at the point of care," lead author Yusuke Shimakawa, scientist in the Epidemiology of Emerging Diseases Unit, Institut Pasteur, said in a news release.²