Accuracy of Saliva as a Diagnostic Medium for Hepatitis B Virus Infection: A Quantitative ELISA Analysis

Abstract

Abstract Context: Diagnosis of hepatitis B virus infection (HBV) has been traditionally serum-based with its attendant risks and invasive procedure. Massive research interests are being directed to the use of saliva for screening, diagnosis, and monitoring of several infectious diseases, including HBV. Various reports suggest that saliva contains biomarkers that are comparable with that of sera. It can also be obtained with minimal risk to the clinician and patient as well. Aim: To determine the diagnostic accuracy of saliva in quantitative detection of hepatitis B surface antigen (HBsAg) using enzyme-linked immunosorbent assay (ELISA). Settings and Design: This cross-sectional analytical study was performed on HBV seropositive patients at the Gastroenterology clinic of the University of Benin Teaching Hospital, Benin City, Edo State. Materials and Methods: Under standardized conditions, equal amounts of blood and saliva samples of 43 HBsAg seropositive patients were analyzed using ELISA to quantitatively detect the concentration of HBsAg. Statistical Analysis Used: The analysis relied on Spearman’s correlation coefficient, linear regression analysis, and Bland–Altman plots to describe the correlational, predictive, and agreements between measurements of HBsAg in sera and saliva. The statistical significance was set at P < 0.05, while a 95% confidence level was used to construct intervals. Results: All participants had detectable levels of HBsAg in both saliva and serum with mean titers of 1.70 ± 0.35 ng/ml and 2.80 ± 0.77 ng/ml, respectively. Correlational and linear regression showed poor fit and predictive relationships of the HBsAg levels. Bland–Altman analysis showed good agreement and no significant bias in their diagnostic agreements. Conclusion: Saliva can be reliably used in screening and diagnosis of HBV infection. There was agreement in their levels independently and within their averages. It may be premature to rely on saliva for quantitative assay of HBsAg in treatment monitoring.