Home health testing kits: what you need to know

An increasing number of home health testing kits can be bought over the counter and online. But are they worth it?

Walk into almost any pharmacy or big supermarket and home testing kits for everything from cholesterol to kidney function now jostle for shelf space with cold remedies and vitamin supplements.

Experts suggest our familiarity with testing for Covid has made us more receptive to these tests, and the worldwide market – worth £13 million in 2021 – is predicted to exceed £35 million by 2031. And of course, the trouble many of us face in seeing a GP can make it tempting to take matters into our own hands. 

On the face of it, it seems like a good idea to know your cholesterol or be able to quash your worries about having bowel cancer by using a simple, at-home test. But it’s more complicated than that, say doctors.

A man getting a blood sample for home health testing kitsCredit: Shutterstock/Southworks
Home health testing kits are on the rise – but are they accurate?

How reliable are at home health tests?

Who’s testing the tests?

Boots and Tesco jumped on the self-test bandwagon earlier this year, selling kits costing as little as £10. This autumn, 5,200 independent pharmacies under the Numark umbrella launched a range of ten kits, including for bowel health, vitamin D and thyroid function.

However, many home health testing kits can be of dubious quality. They also overplay their evidence base and are poorly regulated. Numerous studies have found that many don’t live up to their claims.

“There’s currently only a limited requirement for manufacturers to prove that at-home tests perform well for people who buy them off the shelf. And we don’t yet have the evidence for many that they actually improve health outcomes,” says Oxford GP Dr Gail Hayward at the National Institute for Health and Care Research, who is working to develop better diagnostic tests for GP surgeries.


“People could well be spending money on unnecessary tests, which result in them being sent for more invasive tests that they don’t need.”

A positive result can lead to needless anxiety, treatment and/or a cascade of invasive measures, such as biopsies, X-rays, endoscopies and CT scans – all justifiable if needed.

A negative result, however, may create a false sense of security, leading us to ignore subsequent symptoms.

“False negatives can easily occur when the sample is inadequate, taken in the wrong place, or instructions are not followed – whether based on a finger-prick blood sample, taking swabs from orifices such as the nose, throat or vagina, or urine or poo samples,” says Prof Jon Deeks, a biostatistics expert at Birmingham University, who is investigating home tests.

Prof Deeks is not against home testing per se but says, “Until there are good studies that show the tests are accurate in the hands of those who use them, we do not know how well they work.”

With all that in mind, we take a look at some of the health tests available and whether they’re worth splashing out on.

1. Bowel health check

Results can be ambiguous

What is it? Faecal Immunochemical Test
Cost: £10-£15

The poo test is marketed as a bowel health check and identifies hidden blood in a stool sample, a potential sign of bowel cancer. Once you’ve done the test, a coloured line indicates the presence of blood, a bit like a pregnancy test.

The problem is that without a doctor to interpret the results they can be ambiguous. Haemorrhoids, for example, can cause a positive result. And a negative result doesn’t always mean you’re in the clear. The whereabouts of a tumour can affect whether blood is detected.

Everyone aged 60 to 74 years is eligible for a free test every two years as part of the UK’s national bowel cancer screening programme.

“The difference here is that your sample is analysed in an NHS lab to make sure it is appropriate, and the test done correctly, by a laboratory expert using a quality assured test,” says Prof Deeks.

“The results are sent to you, and if your result showed blood you would be sent an appointment at a local screening centre.”

What are the symptoms of bowel cancer?

Blood in the stools or bleeding from the bottom isn’t the only potential sign of bowel cancer.

Others include:

  • a persistent, unexplained change in bowel habit
  • extreme tiredness
  • unexplained weight loss
  • a pain or lump in your tummy

Dr Lisa Wilde at Bowel Cancer UK says: “Our advice to anyone who is experiencing symptoms or even if things just don’t feel normal for you, is to contact your GP.”

2. Prostate cancer test

More balanced information needed

What is it? Prostate specific antigen (PSA) test
Cost: From £29-£65

This test checks for a protein in the blood of men with prostate cancer. Some of them even promise to give you results right there, without the need to send off samples.


Did you know?

Men over 50 have the right to a free PSA test from their GP. Instead of a national screening programme, there is an informed choice programme, called prostate cancer risk management, for healthy men aged 50 or over who ask their GP about PSA testing. It aims to give men good information on the pros and cons of a PSA test.

While these home health testing kits show your PSA level, that’s only the starting point: a raised level doesn’t necessarily mean you have cancer. Again, the skill of the person interpreting the result is crucial.

“Men need balanced information about the pros and cons, and to be able to talk through their results, which is not possible with an over-the-counter test,” says Amy Rylance at Prostate Cancer UK.

Crucially, PSA tests must be interpreted according to age, says Prof Deeks.

“Tests that detect values of 4 micrograms/litre and above as being positive and those below being negative are misleading,” he says.

“In a man with symptoms, a PSA value as low as 2.5 would be a concern if they are aged 40-49, whereas a value up to 6.5 would not be a concern in a man aged 70-79.”

Worried about prostate cancer? Talk to your GP.

Deeks says there’s no substitute for going to your GP and having proper blood tests taken. He believes these sorts of tests are too simple and can lead to false positives in older men.

“Far better to have a venous blood sample taken and tested in a laboratory to measure the actual PSA concentration,” he says.

3. Thyroid health tests

Thyroid levels really depend on many things

What is it? Thyroid health tests
Cost: Prices start from £9.99

These measure levels of thyroid stimulating hormone (TSH) and can find out whether your thyroid has normal, low, or high function. Some also check for Thyroid Peroxidase (TPO) Antibodies, which are a marker of autoimmune disease affecting the thyroid.

Age is also an issue with these tests.

“Levels of TSH depend on many things and change as we age, so this needs to be considered,” Prof Kristien Boelaert, consultant endocrinologist at the University of Birmingham, explains.

“Over-the-counter tests giving a simple ‘Yes’ or ‘No’ are misleading and could be dangerous.”

The poor quality of accompanying leaflets is another problem identified by Prof Deeks; many don’t contain the guidance needed to interpret results or suggest what users should do next. He feels the rules governing self-tests are unfit for purpose and also points to the difficulty of performing many of them.

“Every time I’ve tried to do a blood test I can’t get enough, and it coagulates,” he says. “This can lead to inaccurate results.”

4. Cholesterol test

A useful starting point

What is it? Home cholesterol test
Cost: Start from £13.50

These tests work by you supplying a sample of blood – from a finger prick – which is then sent off to a lab for analysis.

Regina Giblin, senior cardiac nurse at the British Heart Foundation, says home cholesterol testing may occasionally be a useful starting point for people who struggle to get to the GP.

However, even that isn’t simple: high cholesterol isn’t the only sign of trouble ahead. A more nuanced blood fat profile will be needed, she says.

“Results are best interpreted by a healthcare professional who can help you understand what they mean,” she says.

5. Vitamin D tests

Pretty reliable

What is it? Vitamin D tests
Cost: Prices start from as a little as £7.99

You just need to prick your finger to get a small blood sample and then send this off to a laboratory who will test it for levels of Vitamin D.

Older adults have a higher risk of developing low vitamin D levels, as the bodies’ ability to make vitamin D declines with age. This is why these home health testing kits could be worth buying.

For vitamin D expert Adrian Martineau, professor of respiratory infection and immunity at London’s Queen Mary University, there is some merit in post-to-the-lab vitamin D tests.

“They’re pretty reliable, especially when the lab does LC-MS-MS (liquid-chromatography-tandemmass-spectrometry) testing, the gold standard for measuring vitamin D.”

However, he does suggest checking that any test you buy is performed in an NHS lab or a certified and accredited laboratory – look for ISO certification. Also check for a CE or UKCA mark on any tests you buy.

If you have concerns about your health, you’re almost certainly better off booking an appointment with your GP who can talk over your worries and suggest next steps.


Written by Patsy Westcott