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Hepatitis B Surface Antibody, Quantitative

Test code: 8475

Hepatitis B surface antibody quantitation is used to determine hepatitis B immune status, ie, to determine if the patient has developed immunity against the hepatitis B virus. 1 Such immunity may develop following exposure to the hepatitis B virus or its vaccine.1,2

Patients at higher risk of exposure to the virus include:

  • Infants born to infected mothers
  • Sex partners of infected persons
  • People with more than 1 sex partner in the last 6 months
  • People with a history of sexually transmitted infection
  • Men who have sex with men
  • Injection drug users
  • Household contacts of an infected person
  • Healthcare and safety workers who have contact with blood and body fluids
  • People who have lived or traveled in an area in which hepatitis B is common
  • People who live or work in a prison

Testing is not recommended routinely following vaccination. It is advised only for people whose subsequent clinical management depends on knowledge of their immune status. These people include:

  • Chronic hemodialysis patients
  • Immunocompromised people, including those with HIV infection, hematopoietic stem-cell transplant recipients, and people receiving chemotherapy
  • Infants born to women who test positive for the hepatitis B surface antigen
  • Sex partners of people who test positive for the hepatitis B surface antigen
  • Healthcare and public safety workers who have contact with blood or body fluids

The hepatitis B surface antibody (anti-HBs) is the antibody that is produced in response to hepatitis B surface antigen (HbsAg), a protein present on the surface of the hepatitis B virus. Anti-HBs appears after convalescence from acute infection and lasts for many years. It can also be produced in response to hepatitis B vaccination.2,3

Other hepatitis B antibodies (eg, antibodies against the hepatitis B core and B e antigens) are not produced in response to vaccination. This is because these antigens are not in the vaccine.2,3

An immunometric technique is used. The anti-HBs binds to HBsAg ad and ay subtypes, which are coated on the test wells. Binding of a horseradish peroxidase-labeled HBsAg conjugate to the anti-HBs completes the “sandwich” formation. Unbound materials are then washed away. In the next step, the horseradish peroxidase catalyzes oxidation of a luminogenic substrate, producing light. Light signals are detected and quantified. Intensity of the light is proportional to the amount of anti-HBs present in the patient sample. The result is standardized to an international unit system and reported as milliinternational units per milliliter (mIU/mL).

Results are intepreted as shown in the table below.

Click the table to enlarge in a new window

HBsAg can be detected in the blood 4 to 10 weeks after exposure. This corresponds to onset of symptoms and viremia detectable by nucleic acid amplification methods. Most hepatitis B infections are self-limited and are associated with disappearance of HBsAg within 4 weeks of onset of symptoms. The anti-HBs then appears approximately 4 weeks after natural infection and persists indefinitely.2,3

No. Some acute infections in healthy adults (generally <5%) do not resolve but become persistent. In these patients, antibody response is vigorous and sustained; however, anti-HBs is not detectable in these carriers, because excess circulating HBsAg binds to the antibodies.2,3

No. After 2-3 intramuscular doses of vaccine (depending on vaccine regimen), >90% of healthy adults and >95% of those <19 years of age develop immunity (ie, anti-HBs ≥10 mIU/mL).1 However, there is an age-specific decline in development of immunity.2,3 After age 40 years, about 90% of people become immune, but by age 60 years, only 75% of people become immune.1-3 Larger vaccine doses (2 to 4 times the normal adult dose) or an increased number of doses are required to induce immunity in many hemodialysis patients and in other immunocompromised people.2

References

  1. Atellica® IM Anti‑Hepatitis B surface Antigen 2 (aHBs2). Instructions for use. Siemens Healthcare Diagnostics Inc; 2021.
  2. Centers for Disease Control and Prevention. Hepatitis B. https://www.cdc.gov/hepatitis-b/index.html. Accessed March 27, 2025.
  3. Hepatits B Foundation. https://www.hepb.org/prevention-and-diagnosis/vaccination/. Accessed March 27, 2025.
  4. Ganem D, Prince AM. Hepatitis B virus infection—natural history and clinical consequences. N Engl J Med. 2004;350:1118-1129. doi: 10.1056/NEJM2004091635112

 

This FAQ is provided for informational purposes only and is not intended as medical advice. A physician’s test selection and interpretation, diagnosis, and patient management decisions should be based on the physician’s education, clinical expertise, and assessment of the patient.

 

Document FAQS.105 Version: 1

Version 1 effective 04/30/2025 to present

Version 0 effective 10/31/2013 to 04/30/2025