Understanding the Hepatitis B Surface Antigen blood test

The Hepatitis B Surface Antigen blood test detects the presence of Hepatitis B surface antigen, a protein found on the outer surface of the Hepatitis B virus. When this antigen is present in the blood, it indicates that the virus is actively circulating in the body.

This test is one of the most important and widely used markers for Hepatitis B infection. It is used to identify both acute and chronic infection, often as part of a comprehensive Hepatitis B testing panel. The presence of Hepatitis B Surface Antigen means that a person is potentially infectious, regardless of whether symptoms are present.

Because Hepatitis B infection may remain silent for long periods, surface antigen testing plays a vital role in early detection, public health screening, and prevention of liver-related complications.

When testing for Hepatitis B Surface Antigen is clinically appropriate

This test is recommended whenever there is a need to assess current Hepatitis B infection status. It is commonly used in routine screening, diagnostic evaluation, and monitoring of known infection.

Many people with Hepatitis B experience few or no symptoms, particularly in chronic infection. Blood testing is therefore essential for identifying infection before liver damage becomes advanced.

Testing may be appropriate if you:

• Are being screened for viral hepatitis
• Have abnormal liver function test results
• Have symptoms suggestive of hepatitis
• Have been exposed to blood or body fluids
• Have a sexual partner with Hepatitis B
• Are pregnant or planning pregnancy
• Are undergoing pre-employment or pre-procedure screening
• Have a history of travel or residence in higher-risk regions

Key benefits of the Hepatitis B Surface Antigen test

• Confirms active Hepatitis B infection
  Detects the presence of circulating virus.
• Essential first-line diagnostic marker
  Central to all Hepatitis B testing strategies.
• Identifies infectious status
  Indicates potential for virus transmission.
• Supports early diagnosis and monitoring
  Allows timely clinical follow-up and care.
• Used in both acute and chronic infection
  Relevant across all stages of disease.
• Critical for public health and screening programmes
  Commonly used in antenatal and occupational screening.
• Simple blood test with no preparation required
  No fasting or lifestyle changes needed.
• Provides clarity when symptoms are absent
  Detects infection even in asymptomatic individuals.

How the test is carried out

We offer two convenient UK-wide testing options:

Clinic-based blood testing

• Choose your nearest UK clinic
• A healthcare professional collects a blood sample
• The sample is analysed in a certified laboratory
• Results are issued once testing is complete

Home or hotel blood collection (+£60)

• A qualified phlebotomist visits your home, workplace, or hotel
• Blood is collected at a time that suits you
• No clinic visit required
• Available nationwide across the UK

Both options provide the same laboratory accuracy and clinical reliability.

Understanding your Hepatitis B Surface Antigen results

Antigen not detected (Negative result)

No Hepatitis B Surface Antigen was detected. This indicates no evidence of active Hepatitis B infection at the time of testing.

Typical UK laboratory reporting:

• Negative / Non-reactive

Additional Hepatitis B markers may be needed to confirm immunity or past infection.

Borderline result

A borderline result means the antigen level is not clearly positive or negative. This may occur during very early infection or due to technical factors.

Typical UK laboratory reporting:

• Equivocal / Indeterminate

Repeat testing or further Hepatitis B markers are usually recommended.

Antigen detected (Positive result)

The presence of Hepatitis B Surface Antigen indicates current Hepatitis B infection, which may be acute or chronic depending on duration and other markers.

Typical UK laboratory reporting:

• Positive / Reactive

Further testing is required to assess infection stage, liver health, and infectivity.