3191 Two Cases of False Positive Hepatitis B Surface Antigen With Positive Hepatitis B E-Antigen

Abstract

INTRODUCTION: Hepatitis B surface antigen (HBsAg), is a HBV surface protein particle that indicates current HBV infection. Hepatitis B e Ag (HBeAg) indicates active HBV replication. HBsAg, is a sensitive test, that utilizes anti-HBs to bind to and detect surface antigens to HBV. Any weakly positive HBsAg test needs to be further confirmed using a neutralization test to confirm infection. Below we have briefly described two cases of unusual hepatitis B serology. CASE DESCRIPTION/METHODS: Case 1- 78-year-old Caucasian male, with CKD, was worked up for hepatitis B as he was being considered for dialysis. Initially, on history he had provided positive risk factors (use of illicit drugs and multiple sexual partners) for hepatitis B infection. He denied any recent vaccinations. The transaminases were within normal limits. The hepatitis B surface antigen (HBsAg) was positive. However, the neutralization test was not confirmatory on two occasions. He had hepatitis B e Ag (HBeAg) positive as well. He was negative for Hepatitis B surface antibody (HBs Ab), hepatitis B core total antibody (AntiHBc-T), hepatitis B core IgM (AntiHBc- IgM) and HBV e antibody (anti-HBe). The hepatitis B viral DNA was also negative. The patient was negative for hepatitis C and HIV. The results were similar 6 months later. Case 2- 65-year-old Caucasian male, with psoriatic arthritis, was screened for hepatitis B as part of his management for psoriatic arthritis and was found to have a reactive HBsAg. He had no defined risk factors for HBV. His initial HBsAg was negative 7 years back. His hepatitis B serological profile was similar to the first patient. DISCUSSION: Heterophile antibodies could explain why the confirmatory test for HBsAg, after neutralization, was negative. Our patient had not received the HBV vaccination. Also, it does not explain why the HBeAg would be positive. HBsAg “escape” mutants are generally considered when the HBeAg and/or the HBV DNA is positive, in chronic HBV infection, which was not our case. Though we have come a long way in improving diagnostic laboratory capabilities, we still require better assays to accurately diagnose HBV. Present HBV guidelines do not define our case. We were unable to identify similar case reports. We continue to monitor our two patients, for if we decide to start them on hemodialysis (our first patient) or initiate immunosuppressive agents (for our second patient), the challenges of HBV reactivation are real.