Written by Dr Katie Stephens, GP
Dr Katie graduated from the University of Manchester in 2007 (MBChB) and completed her GP training in the West Midlands in 2012 (MRCGP).
As more people are taking an interest in monitoring their own health, the use of at-home blood test kits has increased. However, there have been concerns expressed over the reliability of at-home testing1, so how do we know which tests are okay to do at home? And what considerations should we make when selecting a health test website?
What are home blood test kits?
As their name suggests, these are kits that people can purchase themselves to do at home, without having to see a doctor first. Typically, a finger prick blood sample is taken using a small lancet. The blood is collected into a vial which is then posted off to a laboratory for analysis. After processing, the results are then sent to the user, with or without clinical interpretation and advice, depending on which company is used. A wide variety of tests are currently available online, ranging from hormone and vitamin levels, to food and chemical ‘allergies’, and even sexually transmitted infections.
What are the benefits of home blood tests?
To start with, there are the obvious benefits of doing any sort of test at home instead of in a clinic. Ultimately convenient, at-home kits mean no phlebotomy appointment booking, travelling, or waiting. There is also the advantage of being able to take some control over your health – if you are curious about whether or not your cholesterol is in a healthy range, you can go ahead and get it checked, as well as decide how closely to monitor it.
On a larger scale, enabling more people to test themselves may mean a greater detection of conditions where people would benefit from treatment (discussed in more detail in my related blog: What are the benefits of home blood tests?)
What are the drawbacks of home blood tests?
From my own perspective as a GP, one of the most important considerations here is: ‘Could this person be falsely reassured by a negative result, when what they really need to do is speak to a doctor?’. With many people turning to Dr Google for diagnoses these days, there is a temptation to rely on information that is readily available, convenient and looks helpful, but may actually be incomplete or inappropriate and therefore harmful in the long term.
Take the symptom of fatigue, for example. Doing tests can be a really helpful first step here, as there are lots of different possible physiological causes that can be picked up in a blood test, such as an underactive thyroid, high sugar level, anaemia, or low Vitamin D level. However, if someone only did these tests and didn’t speak to their GP when all of the results came back normal, they could potentially miss a serious medical condition that wasn’t tested for (not all conditions are picked up by blood tests).
Secondly, with the way that at-home tests are done using a finger prick, typically less blood is collected versus using the traditional method. This blood also comes from a different type of blood vessel – capillaries instead of a vein. This can lead to some concerns over the suitability of finger-prick tests as a direct replacement for the standard venous blood tests.
A helpful study that was published by the BMJ just last year looked into this specific concern and found that, yes, samples taken using a finger prick can be just as reliable as those taken in a traditional way, when it comes to specific tests that are done. Of the few tests looked at, they found this was true for HbA1c (a test of average blood sugar levels, which Kinetik offers), Total Protein and C Reactive Protein (a test for inflammation). It also found that while the results of other tests, including liver function tests (not offered by Kinetik), were not considered ‘interchangeable’ with venous tests, they were still useful for functions like monitoring trends remotely3.
What to consider before purchasing a home blood test kit?
It is worth paying attention to the following considerations.
The results of an at-home test are likely going to have limited use and potentially cause even more questions if they can’t be trusted. With many companies now offering extensive ranges of non-traditional tests, this is certainly something to bear in mind.
In particular, tests that claim to show food sensitivities are ones to be especially wary of, if used without the input of an Immunology Doctor. This is because there is doubt regarding the validity of the science behind the test, which relies on a marker called IgG (short for Immunoglobulin G). In fact, the American Academy of Allergy, Asthma & Immunology specifically advises against using IgG to diagnose food allergies and sensitivities4.
Other tests to look out for are genetic tests that claim to predict how your body would respond to various medications – these are also under scrutiny and warned against by the FDA5.
If a test looks too good to be true, chances are it may well be! Have a chat with your GP if you think you may benefit from a test but aren’t sure if it is trustworthy.
While the equipment used to take at-home tests is regulated (the lancets and viles etc.), you may be surprised to hear that the actual analysis done by private labs is not! This can make it hard to know which private companies to trust.
The good news about using Kinetik’s at-home tests is that they are actually analysed in an NHS lab, which is subject to strict rules and regulations6. This means that you can have the peace of mind that the results you get are accurate. What’s more, any profit made by the lab goes straight back into funding NHS services.
Does the website you are looking at offer clinical feedback on how to interpret your results? For instance, if your Vitamin D level is just slightly below a normal range, the real question becomes ‘What do I need to do now?’. Without someone to give advice on how to act on your results, you may not know whether you should ask for a prescription for high-dose Vitamin D replacement, or just pop over to the chemist for some standard multivitamins.
In terms of medical ethics, the obligation for interpreting test results to you and acting on these results both fall with the doctor who ordered the tests. This then becomes tricky when a test order doesn’t originate with a doctor, but instead originates with the test-taker. That’s why it is extra helpful to ensure that whoever you order your test from is going to give you reliable clinical advice on what to do with your results.
All of the tests that Kinetik offers come with a clear explanation of results and any recommended actions to take based on your result, including whether to simply make lifestyle changes or if you need to make an appointment to speak with your GP.
The bottom line here is that at-home blood tests can absolutely be both helpful and trustworthy, particularly when they are used within their limitations. For those interested in checking their heart health, getting an HbA1c and cholesterol level done is a fantastic idea. You can even plug results into a risk calculator7 to get detailed statistics on your cardiovascular health. Or, for those who are curious to see if a particular condition is causing their symptoms (take fatigue caused by an underactive thyroid, for example), at-home tests are a very convenient and useful starting point, provided they are just one part of the planned course of action, with the second part being involving a doctor.
- Tidy, E. J., Shine, B., Oke, J., & Hayward, G. (2018). Home self-testing kits: helpful or harmful? The British journal of general practice: the journal of the Royal College of General Practitioners, 68(673), 360–361. https://doi.org/10.3399/bjgp18X698021
- Nwankwo L, McLaren K, Donovan J, et al (2021) Utilisation of remote capillary blood testing in an outpatient clinic setting to improve shared decision making and patient and clinician experience: a validation and pilot study BMJ Open Quality 2021;10:e001192. https://doi.org/10.1136/bmjoq-2020-001192