The message is clear: until we get an effective vaccine against Covid-19, the best way to suppress the virus is through efficiently and comprehensively testing people with symptoms so they can self-isolate and minimise its spread. But government Test and Trace targets continue to be missed, and many people report being unable to book a test in their local areas, or even further afield. There remains a disconnect between what 'good' should look like in terms of testing, and what appears to be in place.

As research and development continues apace, here are the current rules and guidance surrounding Covid-19 testing, correct at the time of writing…

Virus tests

Virus (antigen) tests check for current infection with Covid-19. They are available via the NHS Test and Trace programme, and can also be provided by employers, occupational health and other private healthcare providers. The tests use swab samples taken from the nose and throat. A saliva sample can alternatively be used, but this is not routine practice in the UK. Samples are collected by a healthcare professional, or by the patient at home using a self-sampling kit.

The government has also rolled out two new rapid tests, which detect the virus in less than 90 minutes, in hospitals, care homes and labs.

As P3pharmacy was going to press, Boots announced a new swab testing service for asymptomatic individuals, with an instore machine offering results in 12 minutes and a separate 48-hour service pitched at individuals travelling abroad. It is not clear how this sits with public health guidance, or how individuals will view the £120 price tag. 

Antibody tests

Covid-19 antibody tests require a blood sample. A positive result may mean that the patient has previously been infected by the virus.

Free antibody tests are currently being offered to NHS and care staff, as well as to some hospital patients and care home residents. CE-marked tests can also be bought privately, but the GPhC is the barrier to pharmacies offering testing to customers. There are many who think it is time for this position to change (see box, below left).

if you are infected with the virus but the test you use produces a false negative result, you may unknowingly spread the virus to other people

Antibody test blood samples can be collected in several ways. Venous samples can only be collected by a healthcare professional or qualified person. Capillary or finger prick samples can be collected by the patient themselves, or by a healthcare professionals.

For both virus and antibody tests, samples are analysed in laboratories by trained professionals who look for the presence of the virus, or whether the patient has had it in the past.

The MHRA requires all sample collection kits to have a valid CE mark to show they meet minimum safety and performance requirements.

What's happening with self-test kits?

A self-test kit allows a patient to take a sample, test it and then read and interpret the results themselves. This is different to self-sampling, where the sample is taken at home but then sent to a laboratory for testing. The MHRA says there are currently no Covid-19 self-test kits in the UK suitable for home use and it is illegal to supply them for use by members of the public.

Test limitations

The MHRA is clear that “no test is 100 percent reliable – even those with valid CE marks”. It adds that it is important to understand the limitations of Covid-19 tests, stating: “An incorrect or misinterpreted result can lead to a false sense of reassurance. For example, if you are infected with the virus but the test you use produces a false negative result, you may unknowingly spread the virus to other people or not seek the treatment you may need.”

Antibody testing in particular has limitations, with public health bodies stressing that people who test positive for Covid-19 antibodies should not adjust their behaviour because it is still not known whether antibodies offer protection from future infection. It is also not known whether a negative test result means the person has never been infected.