Hepatitis A Virus Antibody test

You do not need to do anything special before this test. A nurse or doctor will take a blood sample from a vein in your arm. No fasting or other preparation is needed. 

What the test measures 

When your body is exposed to the hepatitis A virus — whether through infection or vaccination — it produces proteins called antibodies to fight it. There are two types of hepatitis A antibody, and each tells a different story. 

HAV IgM antibody. IgM (immunoglobulin M) is the first antibody your body makes when you encounter a new infection. It appears early in the illness and is a sign of a current or very recent hepatitis A infection. A positive HAV IgM result means you have had hepatitis A in the last three to six months or so. 

HAV IgG antibody. IgG (immunoglobulin G) develops a little later and then stays in your blood for life, providing lasting protection against further infection. A positive HAV IgG result means you have had hepatitis A in the past, or that you have responded to the vaccination. 

Total HAV antibody test. Some laboratories offer a combined test that detects both IgM and IgG antibodies together. If IgM is negative but the total test is positive, this points to past infection or successful vaccination rather than a current infection.

What your results mean 

If your HAV IgM is positive 

A positive IgM result means you have a current or recent hepatitis A infection — most likely within the last three to six months. This is a notifiable infection, meaning your doctor is required to inform the UK Health Security Agency (UKHSA). Your doctor will discuss what support and monitoring you need. 

Most people with hepatitis A recover fully without specific treatment. Rest, staying well hydrated, and avoiding alcohol are usually recommended while your liver recovers. 

If your HAV IgG is positive and IgM is negative 

A positive IgG with a negative IgM means you have had hepatitis A at some point in the past and are now immune to further infection. This result can also mean you have responded well to the hepatitis A vaccine. 

You do not need any treatment. If this result was to check your vaccination response, it confirms you are protected. 

If both IgM and IgG are negative 

A negative result for both antibodies means you have not had hepatitis A before and are not currently immune. If you have symptoms, further tests may be needed to look for other causes. If you are being assessed for vaccination, this confirms you would benefit from it. 

If your result is negative after vaccination 

A negative test after receiving the hepatitis A vaccine does not automatically mean the vaccine has failed. Laboratory tests may not detect low levels of antibody reliably, and even low levels can still be protective. Your doctor will discuss whether you need any further doses.

If your result confirms a current hepatitis A infection, your doctor will advise you on how to manage your symptoms and prevent passing the virus to others. Good hand hygiene is essential, especially after using the toilet and before handling food. 

Hepatitis A is a notifiable disease in the UK, so your doctor will report the case to the UKHSA. This helps to identify any wider outbreak and protect the community. 

Close contacts who have not had hepatitis A or been vaccinated may be offered vaccination or immunoglobulin (antibody) treatment as a preventive measure. Your GP or local health protection team will advise on this. 

Most people make a full recovery from hepatitis A. The infection does not become a long-term (chronic) condition. Once you have recovered, you are immune for life and cannot be reinfected.

• Timing of the test – if the test is taken very early in an infection, IgM antibodies may not yet be detectable. A repeat test a few days later may be needed if symptoms persist. 
• Recent vaccination – the vaccine stimulates IgG production, so a positive IgG result does not always mean you have had the infection. 
• Low antibody levels after vaccination – laboratory tests may not detect very low levels reliably, even when some protection exists. 
• Other infections or immune conditions – in rare cases, other conditions may affect test results. 

If you have hepatitis A, your doctor may also request: 

• Liver blood tests – to check how well your liver is working and monitor its recovery 
• Hepatitis B virus antibodies – if hepatitis B infection also needs to be ruled out 
• Hepatitis C virus antibodies – if hepatitis C infection also needs to be ruled out 

Hepatitis A is a liver infection caused by the hepatitis A virus. It spreads through contaminated food or water, or close contact with an infected person. It does not become a long-term infection. A safe and effective vaccine is available. For more information, visit NHS: hepatitis A.