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Blood Testing, Elimination Diets and Hair Testing - Which Is The Better Food Intolerance Test?

Updated: Jun 24, 2023

Food intolerance testing - which is right for me?

With so many options for food intolerance testing, and such a huge variation in price, it's easy to get confused as to which method is best for you.

While I've been offering food intolerance testing and support in Sydney CBD for many years, I know that this problem is wide spread and the problem is growing greater by the day.

After seeing an increasing number of patients flying in from locations Australia-wide over the last couple of years, and receiving more and more reports of mismanaged and ill-advised patients, I knew it was time to take action.

My aim is for Food Intolerance Australia to be a one-stop resource to allow all Australians (no matter where they are located) to have access to high sensitivity blood testing and expert Nutritional guidance to assist their recovery from food intolerance. A big part of that is ensuring we offer the most accurate screening process to detect foods which must be eliminated. This allows for a speedy recovery and successful reintroduction.

I wanted to ensure that we were offering the best possible testing method, with the highest accuracy. So, my team and I, along with some willing and helpful patients, have tried and tested the available methods for food intolerance testing.

Here is what we found...

Hair testing for food intolerance

Hair tests promised to be an exciting option. They are convenient, non-invasive, great for those who are needle-phobic and a lovely option for mums wanting to test their little bubs. So while the science doesn't stack up for this testing method, I kept an open mind and excitedly experimented with my team. Let me just say, I really wanted this to work. We were hoping to prove this was a viable option - even if it offered lower sensitivity, as this would allow us to confidently offer this service as an alternative option to our patients.

However: On experimenting with this test I was very disappointed to find that hair testing is a complete farce. I had tested two hair samples, taken from the same person at the same time, under 2 different names. What was returned is two completely different results. The reports couldn't have been more different. On questioning the provider I was not provided any viable reason for this occurrence, or a reassurance that this would not happen again. We conclude that hair testing is not reproducible and therefore not a viable option for testing.

Blood testing for food intolerance

Blood screening of IgG antibodies via the scientifically validated ELISA method is by far the best option for food intolerance testing. The ELISA method is a standard and recognised form of scientific and pathology testing and is the method used for analysis of traditional IgE allergies.

This testing method assesses the blood antibody level in response to the selected foods, and provides a scoring system allowing you to achieve optimum results and minimum confusion over the foods which should or should not be included in your diet.

We tested a variety of IgG tests and have designed a testing protocol with the ideal procedures for preparation, sample collection, sample storage and transport, test analysis (using ELISA method) and results presentation to ensure the highest possible accuracy of results. We have also negotiated with our specialised laboratory to ensure priority results and therefore can offer the quickest results turnaround in Australia for a high sensitivity IgG food intolerance test.

However, we did find that some people were still not getting the best response from their test due to misinterpretation and misunderstanding. Therefore our testing process also includes a personalised report interpretation and additional guidelines from one of our Nutritionists. Each of the Nutritionists on my team have to undergo significant training prior to commencing work with patients and also have to commit to monthly mentoring with me on an ongoing basis. This ensures that every person gets the best possible advice from their IgG food intolerance test and that the recovery method continues to evolve to offer the best results.

Food detective test for food intolerance

This option is a test which can be run quickly and easily by a trained practitioner. In the UK this test is offered direct to the patient, however in Australia we have stricter laws to ensure the safety and accuracy and therefore this test is restricted to health care practitioners.

What we liked about this test is that it offered a quick and easy option with same day results. This allows the patient to quickly move on to their new diet and be relieved of their symptoms in the same time frame that you may spend waiting for results for other tests.

Unfortunately we also found that the test results are open to interpretation and there is a lot of room for human error and had lower sensitivity than the laboratory ELISA method. Many practitioners offer this test while the patient remains in the room, we found the practitioners to be distracted while conducting the test and many did not adhere to the strict guidelines required for optimum results. Timing was off, sample taking was poor and the reagents were diluted causing a possibility of incorrect results. In addition to this, many practitioners forgot to advise patients how to prepare for the test, and did not ask the appropriate screening questions necessary in order to appropriately interpret which are: "have you avoided any foods for the past 3 months or more for any reason", "have you taken any antihistamines in the past 48hours" "are you on any immune altering medications, herbal medicines or nutritional supplements" etc.

Although this was found to have lower sensitivity, when conducted efficiently, in an appropriate environment by a very well trained professional, we did find that the food detective can offer reproducible results and therefore is a viable screening tool. For this reason we continue to offer this option through the website. This test is always conducted by a qualified Nutritionist with additional training in blood microscopy and food intolerance management and recovery. Tests are conducted in absence of the patient so that we can follow exact protocol and focus only on the task at hand.

Elimination Diet Food Intolerance Test

An elimination diet was for a very long time the only testing option for food intolerance. When I first started practicing, this was my only option for food intolerance testing and I was a strong believer in this method. "Why pay for testing when you can modify your diet and see the same results?" I thought. However there are some serious limitations to this testing method.

An elimination diet means to remove all commonly reactive foods at once, and then "rechallenge" them after a period of successful elimination. The patient doesn't begin a challenge phase until he or she has felt significantly better for a period of time. Ideally they should have been completely symptom free for 2-3 weeks.

The rechallenge phase is where each food is then reintroduced one by one and the patient observes their reaction to each food. This can be an effective way of determining what foods are causing symptoms.

However, a large limitation to this testing method is that it relies on symptoms. Many food reactions are asymptomatic (do not cause symptoms) - even some sufferers of Coeliac's disease are asymptomatic. However the destruction of the intestines continues despite them not "feeling" anything. If we relied on this method alone, many coeliacs and food intolerance sufferers would remain undiagnosed.

If a person has very poor gut function and is reacting to many foods, the reintroduction process can take months or even a full year. This can be a costly process for the patient who may be visiting a health care practitioner such as a Nutritionist or Dietitian throughout the process on a weekly, fortnightly or monthly basis. They are likely using supplements to support gut healing, energy, immune function and many of the food reactions they have in the rechallenge phase are increasing the need for these supplements. Basically they take 2 steps forward and 3 steps back.

There was one particular patient of mine who reacted to so many foods that she was in the elimination phase for several months - this caused suffering, weight loss and she was becoming depressed through lack of dietary variety. For me this was the last straw and I immediately began working with food intolerance testing.

Though testing methods have improved in leaps and bounds since then, I still remember how beneficial this test was for my patients. It was like night and day - finally we had all the answers we needed and could get them quickly on their unique diet. One patient who had been on the elimination diet previously was happier, healthier and symptom free within days of her test. She regained the lost weight and even fell pregnant - this was wonderful as preconception was the long term goal. Knowing her ideal diet reduced her risk of miscarriage and assisted her in following the most nutritious diet for her and her baby.

Summary: The elimination diet is highly restrictive and unless guided by a Nutritionist or Dietitian, the patient may develop nutritional deficiencies, and often feels constantly hungry and tired. The food reactions in the rechallenge phase may take a week or more to recover from in some instances which can be extremely traumatic to the patient. Severe weight change is common, most cases this is weight loss (coupled with excessive fatigue) although some, who live on rice porridge and golden syrup (both allowable foods on this diet) may find they gain weight and have increased risk of diabetes. Again, all of this can be prevented when working with a Nutritionist or Dietitian, however this can become very costly if the process is lengthy.


IgG testing via ELISA method through a specialised laboratory offers the most reliable and accurate results. Appropriate preparation for the test, along with appropriate sample collection, storage and transport is vital in order to ensure accuracy. These are the factors taken into consideration when me and my team designed our high sensitivity screening test protocols for Food Intolerance Australia. Our blood samples are collected by trained medical professionals in medical centres and laboratory collection centres all over Australia. The blood test is no different to any test that your GP would refer you for.

The food detective is a viable secondary option if you do not require high sensitivity testing and just want a screening for general interest. However the exact procedure must be followed by a highly trained professional in order to ensure accuracy and to avoid misinterpretation of results.

When The Elimination Diet is Your Only Option

The elimination diet still has a place. Some food reactions do not have any available testing methods such as Histamine Intolerance, Salicylate Sensitivity and Lectin Sensitivity. FODMAP sensitivity has breath testing, however the jury is still out as to whether this is a viable testing method. So in the case of any of these reactions, with no reliable form of testing available, the only method for assessing which foods are causing illness is the elimination diet.

At Food Intolerance Australia me and my team work with a combined approach that incorporates some elimination-rechallenge strategies, while also combining with the latest in scientific high sensitivity testing. We have found that those who remove IgG intolerances generally have a more successful recovery from FODMAP sensitivity, Salicylate sensitivity, Histamine intolerance and Lectin Sensitivity. This is because these reactions are largely due to poor digestive and liver function and removal of IgG reactions allows for a more effective recovery.

With upfront IgG testing I have found that we can improve digestive function, support detox and rebalance the immune system quickly and efficiently. The testing allows us to know exactly which foods can and cannot be used in order to facilitate the healing process and allows us to be more specific in our treatment.

Major Benefit: Often patients who have undergone IgG high sensitivity testing require less restrictive diets throughout their recovery phase than those using experimental methods based on symptom improvement alone such as elimination diet.

Closing Note

I hope that you have found this article to be helpful in your consideration of the available methods for food intolerance testing in Australia.

To choose from our high sensitivity food intolerance tests click here.

Alternatively, you are welcome to visit my Sydney clinic for the onsite 50 foods test by heading to

Kindest Regards

Jennifer May BHSc(NutMed).Adv.Dip.Nut.Med.ATMS.MINDD

Principle Nutritionist & Founder



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