Guidance

Coronavirus (COVID-19): antibody testing

Updated 14 January 2021

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This publication is available at https://www.gov.uk/government/publications/coronavirus-covid-19-antibody-tests/coronavirus-covid-19-antibody-tests

Applies to: England, Wales and Northern Ireland

Guidance on coronavirus (COVID-19) antibody testing

Antibody testing

Antibody tests are used to detect antibodies to the COVID-19 virus to see if it’s likely that you have had the virus before.

The test works by taking a blood sample and testing for the presence of antibodies to see if you have developed an immune response to the virus.

Antibody tests differ to virus swab tests, which test to see if you currently have the virus. An antibody test cannot test if you currently have the virus.

There is no strong evidence yet to suggest that those who have had the virus develop long-lasting immunity that would prevent them from getting the virus again.

Why antibody tests are useful

The value of antibody tests is currently limited to:

  • answering the question of whether someone has had the virus before
  • providing data and a greater understanding on the spread of the virus

Find out more about how your data is used.

What an antibody test cannot tell you

An antibody test cannot tell you:

  • if you’re immune to coronavirus
  • if you can or cannot spread the virus to other people

There is a different test to check if you have coronavirus now.

Whatever your antibody test result, you must continue to follow the same guidelines as everyone else to protect yourself and others from the virus.

Get an antibody test kit

This is the start of the UK’s at-home antibody test kit programme.

Antibody test kits are not widely available.

You can still get an antibody test if you’ve had the coronavirus (COVID-19) vaccine.

Eligibility depends on the job you do and where you live in the UK.

Antibody test kits: check you’re eligible and register for a kit

What your antibody test result means

If you’ve had a coronavirus antibody test, there are 3 types of result you can get:

  • positive
  • negative
  • void

You should get your result within 3 to 7 days of taking the test (usually by text or email).

Positive antibody test result

A positive result means the test did detect COVID-19 coronavirus antibodies so it is likely you’ve had coronavirus before (even if you can’t recall having symptoms). It is not possible to say when.

It does not mean you are guaranteed to be immune (protected) from further infection. You might get the virus again.

It does not mean you cannot spread the virus to others.

Negative antibody test result

A negative result means the test did not detect COVID-19 coronavirus antibodies so it is unlikely you’ve had the coronavirus before.

However, it is possible to have had the virus and receive a negative antibody result. This can happen for some people because they do not develop antibodies, or their level of antibodies is too low for the test to detect.

Void antibody test result

A void result means the test did not work.

There are many potential reasons for this and it’s not possible to tell you the exact one. For example, it could be a problem with the test kit, how the test was carried out (like the blood sample collected was too small) or there was a delay between taking the sample and the lab checking it.

A void result is still important for research purposes.

If you’ve had the COVID-19 vaccine

Vaccines teach your immune system how to create antibodies. But these are different to the ones the antibody test checks for to tell you if you’ve had the virus before. If you’ve had the vaccine, you may be asked to take a different test to check your response to it.

The COVID-19 vaccine will not affect the result of your antibody test.

If you think your result is wrong

The test is accurate but no at-home test is 100% reliable all of the time.

COVID-19 is new and more research needs to be done to understand how our bodies respond to it. For example, we need to find out if antibodies are always produced and how long they last.

If you know you’ve had the virus before, it’s still possible to get a negative antibody result. This can happen for some people because they do not develop antibodies, or their level of antibodies is too low for the test to detect.

If you think you’ve not had the virus, it’s still possible to get a positive antibody result. This can happen for some people because they did not have symptoms or only had very mild ones.

If you have any concerns about your test result, get advice from a health professional.

What to do when you get your result

Regardless of your antibody test result you must continue to follow the same guidelines as everyone else to protect yourself and others from the virus. For example:

Get the latest advice on how to protect yourself and others from the virus.

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