HBsAb test, also known as the Hepatitis B surface antibody test, looks for antibodies against the Hepatitis B virus in the blood. This test helps figure out if there's immunity to Hepatitis B, either from getting vaccinated or from a past infection. When the body makes antibodies, it means it's responded to the virus in some way, giving protection against future infections. This test is especially useful for telling if the Hepatitis B vaccine worked or if there was an infection and developed immunity. Getting this test done is simple - it just needs a small blood sample. Knowing the status of Hepatitis B antibodies can be really important in staying on top of health and stopping the spread of this virus that affects the liver.