Hepatitis B Screening in Singapore: Blood Tests and What a Carrier Result Means

Last updated: 31 Oct 2026

Hepatitis B is a virus that infects the liver. Many people who carry it feel completely well and have no idea they have it, sometimes for decades, until a routine blood test picks it up or the liver has already been damaged.[1][2] Singapore is classed as an area of intermediate hepatitis B prevalence: in a 2010 national survey, about 3.6% of residents aged 18 to 69 tested positive for the virus.[3] Because a simple blood test can show whether you have the virus, whether you are protected against it or whether you have never met it, hepatitis B screening is worth thinking about if you have never been tested.

This guide explains who should consider hepatitis B screening in Singapore, what the common hepatitis B blood tests show and what it means if you are told you are a hepatitis B carrier.

What is hepatitis B?

Hepatitis B is caused by the hepatitis B virus (HBV), which spreads through contact with infected blood and body fluids.[1][2] It can cause two kinds of infection:

• Acute hepatitis B is a new infection. Most adults clear the virus on their own and then become immune.[2][4]
• Chronic (long-term) hepatitis B is when the virus stays in the body. Doctors call the infection chronic if it lasts longer than six months.[4]

The age at which someone is infected makes a big difference. Infection in adulthood becomes chronic in fewer than 5% of cases, but infection in infancy or early childhood becomes chronic in about 95% of cases.[1] This is why passing the virus from mother to baby at birth, which was common before vaccination, is such an important route in Asia.[1][3]

How hepatitis B spreads

The virus can be passed on:[1][5]

• from a mother to her baby during childbirth
• through sexual contact with an infected person
• by sharing needles, or through tattooing, piercing or acupuncture with contaminated equipment
• through cuts from shared razors, nail clippers or other items contaminated with infected blood
• through direct contact with an infected person's open sores.

Everyday contact, such as hugging or sharing a meal, is not one of the ways it is passed on.

Who should consider hepatitis B screening in Singapore?

The World Health Organization recommends that, in places where more than 2% of the population carry the virus, all adults should be offered a hepatitis B test.[1] Singapore's adult prevalence is above that level.[3] Screening is especially worth discussing with a doctor if you:[2][3][5]

• were born before Singapore's universal newborn vaccination programme began on 1 September 1987, and you have never been tested or vaccinated[3][6]
• were born in a country where hepatitis B is common
• have a parent, brother, sister or partner with hepatitis B, or a family history of liver cancer
• have had abnormal liver blood tests
• are pregnant
• have HIV or hepatitis C, or are on kidney dialysis
• are about to start chemotherapy or other medicines that suppress the immune system, because these can reactivate a hidden or past infection[2]
• have shared needles, or have had a tattoo or piercing with equipment that may not have been sterile.

If you are not sure whether you were vaccinated as a child, a blood test can also show whether you are protected.

Hepatitis B blood tests: what each one shows

Hepatitis B can't be diagnosed from symptoms alone, so blood tests are needed to confirm it.[1] A screening panel usually looks for some or all of the following markers.[2][4]

The results are read as a set, not one by one. For example, a positive anti-HBs with a negative HBsAg and negative anti-HBc usually points to protection from vaccination, while a negative result on all three means you have never been infected and are not protected, so vaccination may be advised.[2][5]

What does "HBsAg positive" mean?

A positive HBsAg test means the hepatitis B virus is present in your blood. A single positive result doesn't tell you on its own whether the infection is new or long-standing. If HBsAg is still positive when it's repeated more than six months later, the infection is chronic.[4] Your doctor will then usually arrange further tests to understand how active the virus is and how the liver is doing.

Further tests if you have hepatitis B

If you have chronic hepatitis B, your doctor may suggest:[2][1]

• More blood tests, such as liver function tests, HBeAg (a marker linked with how actively the virus is multiplying) and HBV DNA (the amount of virus in the blood, sometimes called the viral load)
• Elastography (for example FibroScan), a scan that measures the stiffness of the liver. Increased stiffness can be a sign of scarring (fibrosis)
• An ultrasound scan or other imaging to look at the liver and check for cirrhosis or growths
• A liver biopsy, which is only needed occasionally, when other tests don't give enough information.[2]

Your doctor will explain what each test involves, how to prepare and when to expect your results. If you have questions before an appointment, you can send them through our contact form.

Being a hepatitis B carrier: what it means

"Hepatitis B carrier" is the everyday term for someone with chronic hepatitis B. HealthHub describes a carrier as someone who carries the virus permanently in their body and notes that about 1 in 10 people infected with the virus become carriers.[5] Many carriers seldom have symptoms, but they can pass the virus on to others and can develop serious liver problems.[5]

Over many years, chronic hepatitis B can lead to:[1][2]

• cirrhosis, where scar tissue replaces healthy liver tissue
• liver failure
• liver cancer (hepatocellular carcinoma).

Not everyone with chronic hepatitis B develops these complications, and the risk varies a great deal from person to person.[2] It depends on things such as how active the virus is, the state of the liver and other factors like alcohol, weight and family history. That's why regular check-ups are usually recommended even when you feel well. How often you need them is something your doctor will decide with you.

Does every carrier need treatment?

No. Doctors don't treat every person with chronic hepatitis B.[2] Treatment with antiviral medicines is usually considered when blood tests and liver scans suggest the virus could be causing liver damage. These medicines can lower the chance of liver damage and other problems, but they usually need to be taken long term and should not be stopped without talking to your doctor.[2][7]

If you are a carrier, check with your doctor before taking new prescription or over-the-counter medicines or supplements, because some can affect the liver.[2]

Living with hepatitis B

Practical steps that help protect your liver and the people around you include:[2][5][7]

• avoiding or cutting down on alcohol
• keeping to a healthy weight, since extra fat in the liver adds to the strain on it. Our article on fatty liver explains more
• asking your doctor whether you should be vaccinated against hepatitis A
• making sure your partner and the people you live with are tested and, if they need it, vaccinated
• not sharing razors, toothbrushes or nail clippers, and covering cuts
• telling your doctor or obstetrician if you are pregnant, so your baby can be given protection at birth.[3]

Vaccination: protecting yourself and your family

Hepatitis B can be prevented with a vaccine, which gives very high protection.[1] In Singapore, the first dose is given to babies soon after birth as part of the National Childhood Immunisation Schedule, and adults in recommended groups can be vaccinated under the National Adult Immunisation Schedule.[5][8] A blood test first can show whether you already have protection, so you don't have the vaccine unnecessarily.

When to see a doctor

Arrange to see a doctor if:

• you have never had a hepatitis B test and fall into one of the groups above
• you have been told you are a carrier but haven't had a liver check-up recently
• a family member has just been diagnosed with hepatitis B.

Seek medical attention promptly if you have yellowing of the skin or eyes (jaundice), dark urine, pale stools, ongoing nausea or vomiting, or pain in the upper tummy, as these can be signs of active hepatitis.[1][4] For a wider look at what liver problems can look like, see our article on the signs of liver disease.

Dr Ling Khoon Lin sees patients with both digestive and liver conditions. You can read more about the gastroenterology and liver services at the clinic, ask a question through our contact form or request a consultation using the appointment form.

Frequently asked questions

Who should get hepatitis B screening in Singapore?

WHO advises offering a hepatitis B test to all adults in places where more than 2% of people carry the virus, which includes Singapore. It's especially worth testing if you were born before universal newborn vaccination began in 1987, have a family member with hepatitis B, have abnormal liver tests, are pregnant or are starting treatment that weakens the immune system.[1][3]

What is a hepatitis B carrier?

A hepatitis B carrier is someone with a long-term (chronic) hepatitis B infection. Carriers often have no symptoms but can pass the virus on and may develop liver problems such as cirrhosis or liver cancer over time.[5]

What does HBsAg positive mean?

It means the hepatitis B virus is in your blood. If it is still positive more than six months later, the infection is chronic. Further blood tests and liver scans help show how active it is.[4][2]

Is hepatitis B screening a blood test?

Yes. Screening uses a blood test that usually checks for HBsAg, the surface antibody (anti-HBs) and sometimes the core antibody (anti-HBc). Together they show whether you have the virus, are protected or have never been infected.[2]

Can hepatitis B be cured?

Most adults who get a new infection clear it on their own. For chronic hepatitis B, antiviral medicines can control the virus and lower the chance of liver damage, though they don't usually remove it completely.[2][7]

I was vaccinated as a baby. Do I still need a test?

If you were born in Singapore after September 1987 and completed your childhood vaccinations, you are likely to be protected. You may still be tested in some situations, such as pregnancy or before certain medical treatments. Ask your doctor if you're unsure.[3][5]

Can I pass hepatitis B to my family?

Yes, through blood, sexual contact or from mother to baby at birth. It isn't spread by sharing meals or casual contact. Close contacts can be tested and vaccinated if they aren't already protected.[1][5]

Sources

1. World Health Organization. Hepatitis B (fact sheet). https://www.who.int/news-room/fact-sheets/detail/hepatitis-b
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Hepatitis B. https://www.niddk.nih.gov/health-information/liver-disease/viral-hepatitis/hepatitis-b
3. Communicable Diseases Agency, Singapore. Hepatitis B. https://www.cda.gov.sg/professionals/diseases/hepatitis-b/
4. NHS. Hepatitis B. https://www.nhs.uk/conditions/hepatitis-b/
5. HealthHub (Ministry of Health, Singapore). Hepatitis B. https://www.healthhub.sg/health-conditions/hepatitisb
6. The hepatitis B immunization programme in Singapore. Research paper (PubMed Central). https://pmc.ncbi.nlm.nih.gov/articles/PMC2491227/
7. NHS. Hepatitis B – Treatment. https://www.nhs.uk/conditions/hepatitis-b/treatment/
8. HealthHub. Immunisation: inject to protect. https://www.healthhub.sg/well-being-and-lifestyle/pregnancy-and-infant-health/baby-immunisation-inject-to-protect