Hepatitis B virus (HBV) infection is a significant global health issue, affecting over 290 million people worldwide. Chronic HBV infection can lead to severe liver diseases such as cirrhosis, liver failure, and hepatocellular carcinoma, resulting in substantial morbidity and mortality. Accurate and timely diagnosis is essential for effective HBV management, enabling early intervention and treatment. This study evaluates the diagnostic performance of an HBeAg-based test for HBV infection using receiver operating characteristic (ROC) curve analysis. A cross-sectional study was conducted with 98 HBV-positive patients from the University College Hospital, Ibadan. Serum samples were tested for HBsAg, HBeAg, and HBeAb using commercial enzyme-linked immunosorbent assay (ELISA) kits, and HBV DNA quantification was performed using quantitative PCR. Data analysis included calculating the area under the ROC curve (AUC) to assess the test's diagnostic accuracy. Participants included 49 males and 49 females, with an average age of 38.57 years. Clinical characteristics showed that 78.6% of participants were HBeAb-positive and 8.2% were HBeAg-positive. The mean viral load was 100,241.43 IU/mL, ranging from 250 to 1,982,673 IU/mL. HBeAb-negative individuals had a significantly higher viral load compared to HBeAb-positive individuals (p < 0.05), and HBeAg-positive individuals had a significantly higher viral load than HBeAg-negative individuals (p < 0.05). The ROC curve for the HBeAg-based test had an AUC of 0.400, indicating poor discriminatory power. These findings suggest the HBeAg-based test has poor diagnostic performance for HBV infection, underscoring the need for improved diagnostic tools for accurate detection and effective clinical management.