Adapted from BMJ 7 Dec 2024
Advances in diagnostic technology have increased the variety and volume of direct to consumer commercial tests without clinical consultation. In the USA these have surged from $15m in 2010 to $1.15 billion in 2022. These include such tests as covid-19, genetics, HIV, prostate, thyroid, food sensitivity and cancer markers.
It can be argued that these tests provide choice, accessibility and privacy. They can however trigger unnecessary investigation for false positives or false reassurance. The Royal College of Obstetricians and Gynaecologists does not support over the counter tests to measure follicle stimulating hormone to detect the menopause due to poor accuracy. The anti-mullerian hormone test, advertised as being able to predict the chance of conception, is not supported by evidence.
HIV tests have been found to be not accurate enough to rule out infection. Thus a person could be falsely reassured.
In Australia, 40% of online tests are marketed as “health checks.” Testosterone levels can be a gateway to selling testosterone to “optimise” levels. The market for testosterone is $400m in the USA. The American Urological Association has warned that inappropriate use can cause infertility and the Food and Drug Administration is concerned about cardiovascular side effects.
Multicancer early detection tests aim to detect multiple cancers before they become symptomatic. They measure various substances including abnormal DNA. They have not been shown to reduce mortality or to extend life expectancy.
In the USA, the US Preventative Services Task Force recommends screening for breast, cervical, colon and lung cancer. Multi-cancer tests claim to detect over 50 types of cancer. NHS England has announced the purchase of a million of these tests.
In the USA over 6,000 people in seven US medical centres were followed up for one year after having a multi-cancer test. The sensitivity of the test increases as the stage of the cancer worsens, because small cancers tend to shed fewer, harder to detect, fragments of abnormal DNA than larger cancers. Therefore, these tests tend to detect cancers at advanced stages, which tends to limit the benefits of pre-symptomatic diagnosis.
In this group 19 solid tumours were detected, 10 of which already have their own screening tests, and all were late stage, either III or IV. In 57 of the 92 people who had a positive cancer signal, the results were a false positive. To find out what was going on, 88% of the positive group had invasive procedures lasting two to eight months. The economic and emotional costs are considerable.
For some patients, these tests are found helpful due to the difficulty in getting GP appointments. There are calls from various bodies to provide clear information to users as to usefulness and what to do when results are abnormal. Currently most jurisdictions do not have clear definitions, clinical guidelines or regulatory frameworks for direct to consumer tests.
My comment: My husband and I have both used direct to consumer testing and have found them helpful. The reasons we have used them is difficulty in getting GP appointments, as have many others. Popular testing can include blood sugar levels, thyroid levels, lipid testing, and haematinics. Have you found them helpful?
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