The Hepatitis B Surface Antigen ( HBsAg) Test is a blood test used to detect the presence of a protein on the surface of the Hepatitis B virus. It's the primary screening test to diagnose Hepatitis B infection and assess whether someone is currently infected with the virus. Hepatitis B Surface Antigen Test Here are the basic details of the Hepatitis B Surface Antigen Test . A positive result for the HBsAg test indicates that a person has hepatitis B. This test determines if the blood contains the hepatitis B virus's surface antigen. Learn about the HBsAg test. This guide explains its purpose for screening and diagnosing Hepatitis B virus infection , and the simple procedure involved. India's best online pharmacy with a wide range of Prescription and OTC medicines. Order medicines online at 1mg's medicine store in 100+ cities like - Delhi, Mumbai, Bangalore, Kolkata, Hyderabad, Gurgaon, Noida, Pune etc. with free home delivery and exciting offers. Check Now!