Hepatitis B is an infection of the liver that occurs due to the hepatitis B virus (HBV). A person can have a blood test that checks for certain markers, including hepatitis B surface antibodies. These markers can help a doctor identify different phases of the infection and check for immunity.

Hepatitis B is a type of viral hepatitis. Viral hepatitis is the term for liver inflammation that results from a viral infection and can lead to serious complications. Antibodies are disease-fighting proteins that the body develops in response to an infection. Alternatively, a person can acquire them passively through vaccination.

By testing a person’s blood, a doctor can detect the presence of hepatitis B surface antibodies. Testing for these antibodies and additional biomarkers can allow the doctor to confirm an HBV infection or determine whether a person is immune or at risk.

This article explains what hepatitis B surface antibodies are, how hepatitis B blood tests work, and how to interpret the results.

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Hepatitis B surface antibodies, known as HBsAb or anti-HBs, are protective antibodies that develop after a person recovers from an HBV infection or after immunization. The presence of HBsAb suggests that the immune system has successfully developed a protective antibody against HBV, which can provide long-term protection against the virus.

As a 2022 article explains, a serological evaluation, or blood test, for viral biomarkers is a useful diagnostic tool to determine a person’s hepatitis B status. When the immune system detects HBV, it will respond by producing antibodies. By taking a blood sample, a healthcare professional can determine whether an individual has a current infection or whether they are immune or susceptible to infection.

In addition to HBsAb, the blood test will check for the presence of hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (HBcAb). A positive result for HBsAg indicates that a person has a current HBV infection.

HBcAb is a different type of antibody that does not offer protection. A reactive test for HBcAb suggests that a person may have had a previous infection of HBV.

Anyone with symptoms of a hepatitis B infection may benefit from undergoing a blood test. Additionally, the Centers for Disease Control and Prevention (CDC) recommend that doctors screen certain groups of people for hepatitis B, including:

  • people born in places where the incidence of HBV infection is 2% or higher
  • people who inject drugs, such as heroin or steroids
  • individuals who have HIV
  • males who have sexual intercourse with males
  • household and sexual contacts of people with hepatitis B
  • individuals who are taking immunosuppressant drugs
  • individuals with end stage kidney disease
  • donors of tissue or blood
  • pregnant people
  • infants born to individuals with hepatitis B

The test for hepatitis B, known as a hepatitis B panel, is a simple blood test. Although it checks for three different biomarkers, it only requires one blood sample.

A healthcare professional will use a needle and syringe to take a blood sample. They will send this sample to a laboratory, where technicians will test it and then send the results back to the individual’s doctor. The doctor will interpret the results before recommending further action.

Doctors can use the hepatitis B panel test results to interpret a person’s hepatitis B status and recommend the optimal course of action. The table below summarizes the most common explanations of these results.

Interpretation and recommendationHBsAg testHBsAb testHBcAb test
The person does not have hepatitis B, but they are not immune and, therefore, have no protection from hepatitis B. Vaccination is necessary.negativenegativenegative
There is no current infection, but the individual has immunity to hepatitis B as a result of a previous HBV infection. No vaccine is necessary.negativepositivepositive
An individual received their vaccination and is hence immune, without an HBV infection. No vaccine is necessary.negativepositivenegative
The person has hepatitis B. Further testing is necessary.positivenegativepositive
Hepatitis B is a possibility, but the results are unclear. Further testing is necessary.negativenegativepositive

Below, we answer some common questions about hepatitis B and its surface antibodies.

Can you recover from hep B?

Yes, it is possible to recover from hepatitis B. Although there is currently no cure for HBV infection, antiviral medication can help treat chronic infections. In some cases, an individual may require a liver transplant. Receiving an effective vaccine can help prevent an initial infection.

What causes a positive HBsAb test?

A positive HBsAb test result indicates that a person has successfully responded to the hepatitis B vaccination or has recovered from an HBV infection. This suggests that the individual is immune and has protection from future HBV infections.

When should you have the test?

Anyone who has symptoms of hepatitis B may benefit from having the test. Other people who may consider undergoing the hepatitis B panel test are those with known risk factors. These people include individuals born in places with a high incidence of HBV infection and those who use needles to inject drugs.

What is the difference between an antibody and an antigen?

An antibody is a component of the immune system. Its function is to prompt the immune system to respond to potential pathogens, such as viruses and bacteria. It does this by binding to antigens, which are molecules that exist as parts of the invasive pathogens.

What are surface antibodies?

A surface antibody describes an antibody that is able to detect and bind to the surface antigen of a pathogen. It appears after the immune system has cleared the pathogen, such as HBV. People with HBsAb have lifelong protection from future HBV infection.

Hepatitis B is inflammation of the liver that arises due to the hepatitis B virus. A hepatitis B panel blood test can detect a person’s hepatitis B status by checking for biomarkers in the blood. One of these markers is the hepatitis B surface antibody, which protects a person against the hepatitis B virus.

By checking for these biomarkers, a doctor can determine whether an individual has a current infection or is immune or susceptible to infection. They will then be able to recommend suitable treatment options.