Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.


As the COVID-19 pandemic progressed, technology aimed at helping to measure and curb its spread developed rapidly. Antibody tests indicate whether or not an individual has ever been infected with the virus in the past, by measuring whether they have developed antibodies to it. They are used to gain an understanding of the prevalence of the virus in different places and are distinct from diagnostic tests, which test whether an individual is currently infected with the virus.

It’s understandable that the public are eager for solutions that will help put them on a route back to a more normal everyday life, and protect themselves and loved ones from infection, especially those most vulnerable to the disease. At the same time, the quantity of new and quickly changing information about testing for the virus can make this a confusing area for many. Marketers should therefore take care to ensure that they are providing accurate information that does not mislead about their tests’ capabilities and the implications of results for consumers’ lives. 

Ensure the test is legally on the market
Be clear about what kind of test it is
Don't imply that a positive antibody result means the user is immune
Don't mislead about accuracy
Don't make misleading endorsement claims

Ensure the test is legally on the market

Antibody tests are in-vitro diagnostic medical devices and marketers should ensure their test is CE-marked under the relevant regulations.

Antibody tests may involve a blood sample being taken by a health professional at a clinic, or a fingerprick sample being taken at home by the user. In all cases, samples should be assessed by a qualified technician in a lab.

For further information about ensuring tests are in line with regulatory requirements, we recommend reviewing this guidance from the Medicines and Healthcare products Regulatory Agency (MHRA).

Be clear about what kind of test it is

Antibody tests are different from diagnostic tests, and do not indicate whether the user currently has COVID-19. Advertisers should take care not to imply that results of an antibody test will show if a person is currently infected.

Don’t imply that a positive antibody result means the user is immune

At time of writing, CAP understands that there is no strong evidence yet to suggest that those who had been proven to have had the virus and to have produced antibodies are immune. Receiving a positive antibody result does not mean that a person is immune, or that they can’t pass on the virus to others. Because COVID-19 is a new disease, understanding of the body’s immune response to it is limited and it is not known how long an antibody response lasts, whether the antibodies produced are effective in neutralising the virus, and whether having antibodies means a person cannot transmit the virus to others.

The value of antibody tests may be limited to answering the question of whether or not someone has had the virus, and providing data and a greater understanding on the spread of the virus.

This means that, based on current scientific understanding, advertisers should avoid stating or implying that users who test positive for antibodies will be immune to the disease and able to go about normal activities with reduced risk of becoming infected or infecting others.

The ASA recently upheld three complaints about ads for antibody tests. In one instance the ASA ruled that the claims “We are on a mission to safely get you back to your friends and back to work”,“Get your answers”  and referred to “peace of mind” as well as stating “Antibody testing will tell you if you've had the virus and developed an immune response. This is particularly important for asymptomatic people who may unknowingly spread COVID-19 to people they love in high risk groups” misleading implied that the test could inform users whether they were immune to COVID-19 and enable them to get back to work and seeing friends and loved ones without risking spreading contracting or spreading the disease (XMedical Ltd, 14 October 2020).

Similarly, the ASA ruled against the claims “Getting back to work with COVID testing”, “… you might be thinking about getting back to work or the implications of visiting family and friends” and “This simple blood test can tell you within 2 days whether you have potential antibodies (immunity) to COVID 19” (360 Health Ltd, 14 October 2020).

The subject of a third ruling made less overt claims but nonetheless stated that the test showed that users had developed an “immune response”. While technically accurate, the ASA ruled that given the low level of understanding of what antibody tests were for, and the lack of further explanation in the ad, that ad was likely to mislead for similar reasons to the others (Solihull Health Check Clinic, 14 October 2020).

Don’t mislead about accuracy

The ASA has ruled that consumers would understand the claim “100% accurate results” as an indication that the antibody test would detect, without fail and in all circumstances, whether or not a patient had contracted COVID-19. When determining the accuracy of a test, both its sensitivity and specificity must be taken into account. In this case, the ASA concluded that neither the sensitivity rate, nor the specificity rate, when used in isolation, were likely to conform with consumers’ likely understanding of “100% accuracy” as presented in the ad. Furthermore, the advertiser had not provided any information to explain the basis of their claim (Solihull Health Clinic, 14 October 2020).

This is a highly technical area with which consumers are likely to have little familiarity, and businesses are advised to provide information to explain any claims for “accuracy” in simple terms in order to prevent ads from being misleading.

Don’t make misleading endorsement claims

Generally, advertisers must not claim that they or their products have been approved, endorsed or authorised by a public or private body if they have not.

Public Health England has made evaluations of some antibody tests and published those evaluations on its website. However, it does not endorse or accredit tests. As such claims that tests are “approved” by Government or any specific public body such as Public Health England are likely to mislead (Solihull Health Clinic, 14 October 2020).

See also: Coronavirus & COVID-19.


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