Effectiveness and reliability of self-testing kits

There is a growing list of self-test kits that are available to the general public in the UK. Some, like pregnancy, ovulation and diabetes monitors have been available for decades. There are two general types of self-testing kits that are available to the general public - those that require a blood sample to be taken at home and then posted to a laboratory for analysis and those self-tests that give a result within a few minutes, or so, at home. For both types of testing there are strict regulations and international standards to control the manufacturers (ISO 13485:2016), laboratories (ISO 15189:2022), as well as the quality and types of tests available to the general public (IVDD, IVDR). In the EU and UK, self-test diagnostic devices must be independently reviewed by a Notified Body such as BSi, TUV or MDC before being allowed to be sold to the general public. In the UK, the devices must also be registered with the Medicines and Healthcare products Regulatory Agency (MHRA).

During the past 15 years, lateral flow technology originally used in pregnancy tests, has been adapted to detect a wide range of biomarkers, allowing reliable and easy-to-use self-test kits to be made available to help with the detection and diagnosis of common medical conditions. For example, self tests are available for coeliac disease (tTG IgA), bowel cancer screening faecal immunochemical tests (FIT), ovulation prediction (LH), HIV and of course COVID-19 tests. It would be difficult to overstate the positive impact that these easy-to-use, rapid, self-test kits have made to individuals and their families.

The main issue surrounding self-testing is that a diagnosis can rarely be made on the basis of a single test result - whether performed as a self-test or at a hospital laboratory. Medical tests are requested by doctors after they have first taken into account their patient's symptoms and clinical history. This is in contrast to many self-test users who will test first and then need to speak with their doctor to work out how this relates to their symptoms. Some doctors are concerned that the wide-spread use of self-test kits could increase the burden on already overstretched NHS services. Although there is no evidence that patients who self test are impacting the NHS, studies into both the positive and negative effects of self-testing on NHS services are needed, together with discussions as to whether further regulation of the advertising of direct-to-consumer tests is required.

Self-test kits detect the same biomarkers as laboratory tests requested by doctors and have been designed to be reliable, safe and easy to use by anyone at home. Nevertheless, all medical tests, whether performed by a hospital lab, or at home with a self-test kit, will give some people false positive or false negative results. This is because no biomarker is 100% reliable for a specific disease.

For some biomarkers, the number of false positive or negative results can be quite high, so it is important that the general public are aware of the consequences that a test result may have before purchasing a self-testing kit.

  • False positive results may cause unnecessary worry and may prompt unnecessary investigations or doctor's appointments
  • False negative results may give reassurance that the patient is healthy when they may have a medical condition that requires treatment

Manufacturers of self-test kits should consider these factors during the design of the device, the information provided to the user and promotional materials.

In summary, all medical tests will give some people false positive or false negative results which could lead to unnecessary further investigations and treatment, or risk a missed diagnosis. Before deciding to purchase or use a self-test kit the pros and cons of using the test should be carefully weighed up and what the result will mean to the user. Nevertheless, self-test kits, when used responsibly, have the potential to raise health awareness and help diagnose a medical condition sooner.

SELFCHECK is a range of self-testing kits, assembled in the UK, CE certified according to IVDD/IVDR and registered with MHRA. SELFCHECK is available from major retailers, and direct from the manufacturer, who also provide comprehensive technical support. For the current range see www.selfcheckmedical.com