Professor Patrick Holford argues that home-tests for health conditions empower individuals and this may account for their unpopularity with some health professionals:
some health professionals just haven’t kept up to date. Perhaps it’s because a ‘home test’ takes the power away from the professional and puts it in your hands.
This is a remarkable slur against “some health professionals”, particularly when there are well-formed objections based on expert opinion that, e.g., there is not a sufficient quality or quantity of clinical evidence to support a role for IgG testing in the diagnosis of food intolerance (and again).
Allergy and Food intolerance tests
Although Holford finds the scientific proof for the IgG test “deeply impressive” the expert consensus on this topic is so striking that even the Advertising Standards Authority has issued an opinion on IgG home tests for food intolerance:
the evidence submitted was not sufficiently robust to prove the efficacy of the tests for diagnosing food allergy or intolerance.
In 2006, the House of Lords appointed a committee to investigate allergy and allergic disease in the UK. The committee produced a comprehensive report HL 166-I (pdf from which pg numbers are given). The committee makes a number of good recommendations and provide some useful summaries. Pages 86-88 cover the issue of direct-to-consumer tests such as the YorkTest foodSCAN IgG test for food intolerance and the YorkTest-Allergy UK MAST IgE test for allergies to food and airborne allergens, amongst others which may be taken as representative of similar direct-to-consumer testing products.
Dr. Gill Hart, Technical Director of YorkTest Laboratories, a company which manufactures such tests, told us that the presence of either IgE or IgG antibodies does not necessarily prove whether a food allergy exists, but claimed that IgG could be used “as a marker that a reaction has occurred” (Q 742). However, there is limited evidence to support this claim.
Furthermore, the EAACI even discredited the use of well validated tests based on IgE antibodies if they are used on a self-testing basis. This was because the tests “cannot be interpreted without a detailed clinical history taken by an allergy-trained individual, thus over the counter and postal testing is open to misinterpretation unless expert opinion is available” (p 70)…
Dr Hart admitted that the mechanisms used in the tests were “unclear…”…
The House of Lords Committee summed up their advice as follows (pg 87):
We are concerned both that the results of allergy self testing kits available to the public are being interpreted without the advice of appropriately trained healthcare personnel, and that the IgG food antibody test is being used to diagnose food intolerance in the absence of stringent scientific evidence…We urge general practitioners, pharmacists and charities not to endorse the use of these products until conclusive proof of their efficacy has been established.
The House of Lords Committee members align themselves with clinical experts in their notion of who is qualified to diagnose allergies and allergic disease (hint, it is not the typical holder of a Diploma ION nor an auto-didact nor self-proclaimed expert; pg 89):
An accurate diagnosis is key to treating an allergic condition adequately, and much depends on taking an accurate patient history with details of a patient’s symptoms, home and occupational environment, temporal and geographic features, relevant family history and any physical signs. Diagnostic tests are often based on skin tests, blood tests and challenge tests. But the results of tests are meaningless in isolation; they have to be interpreted in the context of the patient history, a difficult task which requires a solid training in allergy.
Holford has an unusual view of empowerment if it encompasses persuading people that they should spend £250 pounds on an IgG blood test to diagnose food intolerance when there is a good deal of expert opinion that dismisses these tests as irrelevant.
If people suspect that they have an IgE allergy, then they should consult an appropriately-qualified clinician. Allergies may vary in the severity of their presentation but they may need expert diagnosis and management by a clinician whose practice is founded in evidence-based interventions rather than advice on tests, supplements and exclusion diets from an auto-didact.
direct to consumer tests
The House of Lords Committee expressed reservations about direct-to-consumer tests that might well apply to several other tests that Holford promotes and endorses: e.g., the Liver Check or the test for Coeliac Disease. For some of these tests, if consumers were to have a positive result, then they might have to approach a GP for further testing, referrals and validation.
Coeliac Disease Self-Test Even where there is a negative result from a blood test or similar, if someone were concerned that they might have Coeliac Disease, then they should consult a GP. It is still possible that people can manifest clinical symptoms in the absence of a positive blood test: e.g., an endoscopy or colonoscopy might discover clinical findings for Coeliac Disease although the blood test is negative.
We have previously commented that the Biocard Coeliac test that Holford promotes is validated for very high specificity and sensitivity when used by appropriately trained and experienced personnel. It is possible that the Biocard Coeliac test has a very different accuracy when used by the general consumer who is (presumably) seeing and using the test for the first time. Even District Nurses who had received some training in the use of the test mis-interpreted the results which reduces the test’s accuracy; presumably this is even more true of the general consumer.
Liver Check Test Holford is presently engaged in promoting the Liver Check test to accompany his new 9 day detox plan. He claims:
LiverCheck is a home finger prick blood test that allows you to check the health of your liver…Liver check tests specifically for damage to your liver cells by testing for two enzymes: ALT and AST.
The Patient UK site offers an excellent account of what a thorough Abnormal Liver Function Test panel should cover. They argue that patients should “[i]n the first instance request the following: albumin, bilirubin, ALP, GGT, AST, ALT and INR.” In other words, a LiverCheck test – which just looks at ALT and AST in the blood – is not as thorough as one might hope.
Patient UK also points out that “Liver function tests are easily obtained”. Those seeking such a test are therefore left with a choice between seeing their doctor (either on the NHS or privately) to get a more thorough liver function test (LFT), or buying a less thorough LiverCheck test. Did I mention that Health Products For Life sells the LiverCheck test for £150, while the more comprehensive NHS test panel is free to patients?
If you were to have a LiverCheck test, there are also issues around interpretation. Patient UK notes the following about LFTs
many patients have asymptomatic abnormalities in liver function tests…It is important to remember that the “normal” values are within ± 2 standard deviations meaning that 2.5% of a healthy population will have abnormal liver function tests.
In other words, one might have non-standard test results that do not indicate a liver problem which will impact on one’s health. It is therefore important to have a qualified medical professional to interpret the results of these tests.
On the other hand, one might have abnormal results that are within range depending upon other items in the medical history such as statins use or for many other reasons. It should not be left up to a lay-person to interpret the signficance or not of any results.
If your liver isn’t working properly, this is serious – see your doctor ASAP if you suspect that this is the case, or if you think you may have done something to damage your liver. Likewise, if you’re doing something that’s obviously bad for your liver – for example, if you’re drinking alcohol to excess – or you have other concerns then please consult an appropriately-qualified doctor.
Homocysteine Test Holford is remarkably keen on promoting the homocysteine test to the point where he advocates that it should be taken 2-3 times a year. We have outlined the objections of Dr Steve Murphy who is an expert in genetics and personalised medicine. Murphy makes a powerful and persausive argument that you would need a skilled interpretation of your homocysteine levels alongside your clinical history: it might be very unwise to self-medicate to adjust homocysteine levels without allowing for relevant clinical details. And, further, it is still unclear that altering your homocysteine levels would reduce your risk of developing certain symptoms or diseases, whatever Holford’s assertions to the contrary.
Assorted Tests Finally, it is a herculean labour to keep up with the dizzying array of dubious tests that Holford recommends as part of an individual’s empowerment. It is fair to say that these are tests that you would not find in a testing facility that is engaged in evidence-based tests for particular conditions. These are not tests for which you will find support in the clinical or scientific literature. E.g., hair mineral analysis; Candida Antibody Profile Test; Detoxification Profile Test.
Holford affects to believe that “some health professionals” object to loss of their authority and this is why they object to some of these direct-to-consumer tests. Health professionals have substantial ethical, practical and clinical concerns about some of these tests. It is difficult to understand why persuading people to spend large sums of money on irrelevant or dubious tests (and the supplement pills that are frequently recommended as a response to those test results) is empowering for them; however it is easy to see that it may be rewarding for those who promote these tests and pills.