Hepatitis B Testing

A HBsAg (Hepatitis B surface antigen) test uses a blood sample taken from the vein. The test detects hepatitis B surface antigen (HBsAg), indicating a current hepatitis B infection.

If the result is positive, the blood sample will be sent to a laboratory for further testing to determine whether the infection is acute or chronic.

If the laboratory tests determine that the virus has resided in the body for less than 6 months and is fairly new, this is known as an acute Hepatitis B infection. A blood test will need to be done after 6 months to determine if the virus still remains.

A chronic infection means that the virus has resided in the body for more than 6 months. Most people with chronic Hepatitis B are able to live a long, full life.

Here are a few tips on how to prepare for your appointment:

• Try to remember (as much as possible) the details of why you are visiting. For example, if you are showing symptoms, try to remember when these started and the potential cause of exposure.
• Drink lots of water beforehand to ensure that you are well hydrated and your veins are visible and easy to find. This ensures that we are able to take your blood sample as smoothly as possible. You do not need to hold your urine.
• Relax, Clarewell Clinics is a safe space. Your medical history with us is completely confidential so you can be as open and honest as you wish to be with us.

The window period for an instant Hepatitis B surface antigen (HBsAg) test is typically 4 to 12 weeks after exposure. Although the virus may be detectable earlier in some people, it usually takes 4 to 8 weeks for HBsAg to reach detectable levels.

For the most reliable result, it is generally recommended to test 12 weeks after exposure. If you think you have been exposed within the last 48 to 72 hours, seek medical advice as soon as possible, as preventive treatment may still be an option.

Instant Hepatitis B testing detects the Hepatitis B surface antigen (HBsAg), a protein found on the surface of the virus that appears early during infection.

The test uses lateral flow technology. A small blood sample is applied to a test strip containing antibodies that bind specifically to HBsAg. If the antigen is present, a visible line appears on the test strip, providing a result in around 30 minutes. Because the test detects hepatitis B surface antigen rather than your body's immune response, it can identify a current infection early.

Instant Hepatitis B tests are highly accurate for detecting the Hepatitis B surface antigen (HBsAg), with performance varying slightly depending on the specific test used. When performed at the appropriate time after exposure, rapid tests provide reliable results.

Testing too soon after exposure may produce a false-negative result because the virus has not yet reached detectable levels. For the most reliable result, testing is generally recommended at least 60 days after exposure, with 12 weeks providing the most conclusive result.

You should get tested for Hepatitis B if you have known exposure (for example, if you have had sex or shared a needle with someone who has the infection), you are a sex worker, drug user, engage in chemsex, having lived in, travelled to, or received healthcare in a country where hepatitis B is more common, or if you are experiencing any of the following symptoms:

• High temperature
• Tiredness
• Pain in your stomach
• Feeling nauseous or being sick
• Itchy patches on your skin
• Yellowing of the eyes and skin

Most people have mild or no symptoms but may still be infected. It is important to get tested to ensure that you are not at risk of passing the infection to others, should you have it.

No. A physical examination is not usually required for an instant Hepatitis B test.

The test only requires a blood sample. Your clinician will discuss your medical history and any potential risk of exposure. If you have symptoms or other sexual health concerns, a physical examination may be recommended as part of a broader assessment.

Although Hepatitis B can be transmitted through semen, vaginal fluids and blood, it is a blood virus and resides in your blood. Therefore, HBsAg is detected in a blood sample, making blood the appropriate specimen for testing.

Testing too soon after exposure may result in a false-negative result because the virus may not yet be detectable. We will review the timing of your possible exposure before testing. If you are taking antiviral medication, we will also discuss how this may affect the test results before carrying out the test.

Apart from the routine Hepatitis B test, there are several other blood tests available to diagnose and monitor people with Hepatitis B. They can be used to distinguish acute and chronic infections.

Hepatitis B surface antibody

This test looks for Hepatitis B surface antibodies. If this test result is positive, it means that you have antibodies in your system to fight and protect you from the virus. These antibodies could be a result of having the Hepatitis B vaccine or successfully recovering from a Hepatitis B infection in the past.

Hepatitis B core antibody

This test looks for Hepatitis B core antibodies. A positive anti-HBc indicates previous or current hepatitis B infection and should always be interpreted alongside other hepatitis B markers. The difference is that core antibodies do not protect you from the virus like the surface antibodies do. This test can only be understood in light of the HBsAg and anti-HB (HBsAb) test. Your healthcare provider will be able to explain your Hepatitis B following all three test results.

Hepatitis B E antigen + antibody

This test helps to determine your infectiousness. The presence of the Hepatitis B E antigen is associated with higher Hepatitis B DNA levels. Thus, revealing how infectious you may be.

Hepatitis B viral load (DNA PCR)

To monitor the effectiveness of Hepatitis B treatment.

You can receive your test results by either text or email.

The results will be either NOT Detected (i.e. negative) or DETECTED (i.e. reactive).

In some cases, the test may come back as equivocal which means that it was not possible to gain a conclusive result from the sample given. If this happens, we will request another sample free of charge.

If you think you have been exposed to hepatitis B, seek medical advice as soon as possible. Post-exposure vaccination, with or without hepatitis B immunoglobulin (HBIG), may be recommended depending on the nature and timing of the exposure.

It is essential to practise safe sex whilst waiting for your test results. This includes not having multiple partners and using condoms at all times. You should also avoid doing anything where your blood can come in contact with another individual (e.g. sharing needles, toothbrushes, body piercing jewellery).

You should also cover any cuts you may have that could easily reopen and bleed.

If your Hepatitis B test is positive, we will send your sample to the laboratory for confirmatory testing. If the diagnosis is confirmed, additional tests will be carried out to determine whether the infection is acute or chronic.

It is essential to tell any partners you may have that you have tested positive so that they can seek testing and vaccination if appropriate, and prevent the infection from spreading to other people.

You may have tested before the virus has time to show itself in the body, or luckily - you may have not contracted the virus. Your clinician will advise you on whether you should retest at a later date or get vaccinated.

Yes, we provide a certificate of testing.

Please let us know at the time that you would like a certificate of testing and bring a proof of ID (passport or driving licence).