Shop-bought health tests not always fit for purpose, researchers warn

The team said that in the future, home tests could have great potential for patient care. File picture

Off-the-shelf health tests for issues such as high cholesterol, vitamin deficiency, fertility and prostate problems are not always fit for purpose, experts have warned.

A team from the University of Birmingham examined tests that people can buy in supermarkets and shops and which they then use at home.

They found the tests risked giving people the wrong result, could delay diagnosis, and most of them recommended follow-up with a doctor anyway, regardless of the result.

The researchers called for much tighter regulation of the sector. "In the absence of guidance from healthcare professionals, individuals might use tests inappropriately or without a clear understanding of the implications of the results.

"False positive test results can lead to unnecessary anxiety, increased healthcare usage, and additional costs, whereas false negative test results may delay appropriate treatment or engagement with... screening programmes.

"Test errors can stem from inherent limitations in the accuracy of the test, as well as user-related issues such as sampling errors, incorrect processing, and difficulties in interpreting the results."

However, the team said that in the future, home tests could have great potential for patient care.

Professor Jon Deeks, from the University of Birmingham, said: "A plethora of new health self-tests have emerged in recent years and are available to buy from many high street supermarkets and pharmacies in the UK.

"While these kits have been approved for sale, they are not subject to the same stringent regulations as pharmaceutical products.

"Our recent research raises concerns about the suitability, accuracy and usability of many of the self-testing products available that require users to sample, test and interpret results themselves.

"In some cases, it is unclear how accuracy claims are supported, and there is no requirement of manufacturers to share the evidence behind these claims."

Prof Deeks said much of the literature contained with tests was "not easy to understand", while some of the results could lead to a "wrong diagnosis".

In one example, he said the self-tests for prostate-specific antigen (PSA) levels, a marker of prostate health, were fixed at a certain concentration level.

However, "if you're age 70 you need to have your PSA done at a very different level to when you're 20", he said.

Overall, 30 self-tests were included in the study, published in the British Medical Journal (BMJ).

The tests covered 19 different conditions, including vitamin deficiency, blood sugar levels, cholesterol, thyroid function, prostate health, HIV, menopause and bowel cancer.

Researchers said only eight of the 30 tests provided information about who should or should not use the test, while four specified the presence of symptoms.

Less than half of the test boxes (14) included any statement about test accuracy.