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Antibody to Hepatitis B Surface Antigen (IgG) - Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test checks for antibodies against the hepatitis B surface antigen, which your immune system produces in response to past or potential hepatitis B infection. It helps determine immunity status after vaccination or recovery from infection.

Quick summary

["Assesses immunity to hepatitis B virus through antibody detection."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
49100-1
Short code
H2a-H2b DNA IgG Ser Ql
Synonyms
H2a-H2b DNA IgG Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test to verify immunity after hepatitis B vaccination, screen for past infection, or evaluate exposure risk. It’s also used in newborns to check if they received protective antibodies from their mother.

How the Test Works

A small blood sample is taken, and the serum/plasma is analyzed using an immunoassay method to detect IgG antibodies specific to hepatitis B surface antigen. This identifies whether your immune system has recognized and responded to the virus.

Sample Collection and Preparation

A vein in your arm is cleaned and a needle is inserted to draw blood. The sample is then processed to separate serum or plasma for testing. This is typically done in a lab setting.

Test Results Interpretation

Positive results indicate immunity (either from vaccination or prior infection). Negative results suggest no detectable antibodies, meaning you may not be immune and could be at risk of infection if exposed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Anti-HBs (IgG)

Frequently asked questions

A positive anti-HBs result confirms protection against hepatitis B, reducing the risk of infection. It’s critical for travelers, healthcare workers, and individuals with high exposure risk. A negative result may prompt further testing (e.g., hepatitis B surface antigen) to assess active infection status.
This test alone cannot diagnose acute hepatitis B. If you suspect exposure, discuss additional testing with your provider.
What does a positive anti-HBs mean?
A positive result means your body has developed antibodies against hepatitis B, indicating immunity—either from vaccination or recovery from infection. This protection lasts long-term if vaccinated or naturally acquired.
How often should I get this test?
Your provider will determine frequency based on your risk factors (e.g., vaccination status, exposure history). Typically, it’s done once after vaccination or annually for high-risk individuals (e.g., healthcare workers).
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy