Table of Contents
- Introduction
- Understanding the Difference: Allergy vs. Intolerance
- What Is MRT?
- The Role of Mediators in Inflammation
- The Debate Around Sensitivity Testing
- The Smartblood Method: A Phased Journey
- Comparing MRT to IgG Testing
- Practical Scenarios: How Testing Helps
- Implementing Your Results (The Reintroduction Phase)
- The LEAP Diet vs. The Smartblood Approach
- Why Choose Smartblood?
- Conclusion
- FAQ
Introduction
Have you ever finished a meal, perhaps a simple Sunday roast or a quick weekday pasta, only to find yourself plagued by a dull headache, nagging bloating, or an overwhelming sense of fatigue a few hours later? These "mystery symptoms" can be incredibly frustrating. They aren’t quite severe enough to send you to A&E, but they are disruptive enough to drain your energy and leave you feeling less than your best.
When symptoms linger and your GP has ruled out underlying medical conditions, it is natural to start looking at your plate. This search for answers often leads people to the world of food sensitivity testing. If you have been researching online, you may have come across the term "MRT" and wondered what it entails. For a practical, step-by-step primer on finding food intolerances (and a free elimination chart), see our guide to how to find food intolerance.
In this article, we will take a deep dive into what the MRT food sensitivity test is, how it functions, and how it differs from other methods like IgG testing. We will explore the science behind "mediators," the debate within the medical community regarding these tests, and how you can use testing as a constructive tool within a wider health journey.
At Smartblood, we believe that understanding your body should be a structured, calm process. We advocate for a phased approach: always consulting your GP first, attempting a managed elimination diet, and only then considering a test to provide a clear "snapshot" to guide your progress. Our goal is to help you move away from guesswork and toward a more informed relationship with the food you eat.
Understanding the Difference: Allergy vs. Intolerance
Before we explore the specifics of the MRT test, it is vital to distinguish between a food allergy and a food intolerance (or sensitivity). These terms are often used interchangeably in casual conversation, but in a clinical sense, they represent very different bodily responses.
Food Allergy (IgE-Mediated)
A food allergy is a rapid and sometimes dangerous reaction by the immune system. It involves a specific antibody called Immunoglobulin E (IgE). When someone with an allergy eats a trigger food, their immune system overreacts almost immediately, releasing chemicals like histamine into the bloodstream.
Symptoms of a food allergy usually appear within seconds or minutes. They can include hives, swelling of the lips or tongue, and difficulty breathing.
Important Safety Note: If you or someone you are with experiences swelling of the face, lips, or throat, wheezing, extreme difficulty breathing, or a sudden drop in blood pressure (collapse), this may be anaphylaxis. This is a medical emergency. You must call 999 immediately or go to the nearest A&E department. Food intolerance tests are not appropriate for managing these severe, immediate reactions.
Food Intolerance and Sensitivity (Non-IgE)
Food intolerances and sensitivities are typically much slower to manifest. Unlike allergies, which involve the IgE pathway, sensitivities often involve different parts of the immune system or digestive system.
The symptoms—such as bloating, diarrhoea, migraines, skin flare-ups, or joint pain—can appear several hours or even up to three days after eating the food. This delay makes it incredibly difficult to pinpoint the culprit through memory alone. This is where testing, such as IgG analysis or MRT, aims to provide clarity.
If you’d like quick answers to common questions about testing, our FAQ page covers ordering, sample collection and result interpretation.
What Is MRT?
The Mediator Release Test (MRT) is a patented blood test designed to identify food sensitivities by looking at how your white blood cells react to different substances. While many traditional sensitivity tests look for specific antibodies (like IgG), the MRT takes a "functional" approach.
Instead of measuring the level of a specific antibody, the MRT measures the result of the immune reaction. When your immune system identifies a food it doesn't like, it triggers the release of various chemical messengers called "mediators." The MRT aims to quantify this release.
The Science of Volumetric Changes
The technical process of an MRT involves taking a blood sample and exposing it to various food extracts and chemicals in a laboratory setting. A specialised machine then measures the physical changes in your white blood cells—specifically neutrophils, monocytes, eosinophils, and lymphocytes.
If the white blood cells shrink in size after being exposed to a specific food, it indicates that they have released their internal "mediators" (such as histamines, cytokines, and prostaglandins) into the surrounding plasma. The test measures these volumetric changes. The more the cells shrink, the higher the "reactivity" score for that particular food.
What Does an MRT Panel Usually Cover?
An MRT panel typically looks at around 170 to 180 different items. This includes common foods like dairy, wheat, and eggs, but it also extends to food chemicals and additives such as:
- MSG (monosodium glutamate)
- Certain artificial sweeteners
- Food colourings and dyes
- Caffeine
- Natural food chemicals like salicylates
Because MRT focuses on mediator release rather than a single antibody type, it is often described as a broad "functional" snapshot of immune reactivity.
The Role of Mediators in Inflammation
To understand why someone would choose an MRT test, we need to understand what "mediators" actually do in the body. You can think of mediators as the body’s internal alarm system.
When your immune system perceives a food protein as a "threat," it instructs white blood cells to release these chemicals. While this response is intended to protect you, it often causes collateral damage in the form of inflammation.
- Histamine: Can lead to swelling, itching, or digestive upset.
- Prostaglandins: Often linked to pain and inflammation, potentially contributing to headaches or joint discomfort.
- Cytokines: Broad chemical signals that can cause systemic symptoms like fatigue or "brain fog."
Because there are many different types of mediators, proponents of the MRT argue that measuring the total release is more comprehensive than measuring just one type of antibody. If you want to explore the scientific debate and relevant studies, our Scientific Studies hub collects the research we reference.
The Debate Around Sensitivity Testing
It is important to acknowledge that food sensitivity testing—whether it is MRT or IgG testing—is a topic of ongoing debate within the medical community.
Mainstream organisations, such as the NHS or the British Dietetic Association, often point out that these tests lack the rigorous clinical validation required for a medical diagnosis. For example, they may argue that the presence of certain antibodies or cell changes could simply be a sign of "exposure" to a food rather than a true clinical sensitivity.
At Smartblood, we agree that these tests should never be used as a standalone diagnosis. We do not claim that our tests, or any sensitivity test, can "cure" a disease. Instead, we view testing as a highly useful information tool: a snapshot to help prioritise what to trial in an elimination diet.
If you want practical help interpreting results, our article on how to read food intolerance test results explains the 0–5 scale and how to turn data into action.
The Smartblood Method: A Phased Journey
If you are struggling with mystery symptoms, we always recommend following a structured path. Testing should not be your first port of call. Instead, we encourage what we call the Smartblood Method.
Phase 1: Consult Your GP
This is the most critical step. Many symptoms of food intolerance overlap with serious medical conditions. Before looking at food sensitivities, your GP should rule out:
- Coeliac disease
- Inflammatory bowel disease (IBD)
- Thyroid issues
- Anaemia
- Infections
Phase 2: Symptom Tracking and Elimination
Once your GP has given you the "all clear" from a medical perspective, the next step is to observe your own body. We provide a detailed guide on how to find food intolerance that includes a free elimination diet chart and symptom tracker to help with this phase.
For two to four weeks, keep a detailed diary of everything you eat and every symptom you experience. If you notice a clear pattern—for example, you always feel bloated after eating Greek yoghurt—you can try removing that specific food for a trial period. This simple step can often provide all the answers you need without spending money on testing.
Phase 3: Structured Testing
If you have tried an elimination diet but your symptoms are still present, or if your reactions are so delayed that you cannot find a pattern, this is when testing becomes valuable.
A test provides a "snapshot" of your body's current reactivities. It helps narrow down a long list of potential culprits to a manageable few. Instead of guessing whether it’s wheat, dairy, yeast, or tomatoes, you have data to guide your next move. For details on the testing process and what to expect, see our How It Works page.
Comparing MRT to IgG Testing
While the MRT focuses on white blood cell changes, IgG testing measures antibody levels (IgG immunoglobulins) in the blood. Smartblood’s approach uses IgG analysis because it is highly standardised and straightforward to map onto a reintroduction plan.
MRT (Mediator Release Test)
- Functional: measures mediator release via volumetric white cell changes.
- Typically covers ~170–180 items.
- Used in the LEAP protocol by some clinicians.
IgG (ELISA-based) — Smartblood’s Approach
- Measures levels of IgG antibodies to specific food proteins using ELISA.
- We report results on a clear 0–5 reactivity scale to help prioritise foods.
- Our kit covers a broad panel of 260 foods to give a comprehensive picture; you can order the Smartblood Food Intolerance Test online if you decide this is the right next step.
Both approaches have their strengths. MRT may capture functional mediator activity, whereas IgG panels provide a reproducible antibody profile that many clinicians find practical for structuring elimination and reintroduction.
Practical Scenarios: How Testing Helps
To see how this works in real life, let’s look at two common scenarios where a structured approach makes a difference.
Scenario 1: The 48-Hour Delay
You suffer from migraines and suspect food as a trigger, but the headache arrives 48 hours after a meal. By the time the headache appears you’ve eaten many other meals, so it’s hard to be sure. A Smartblood IgG result highlighting a high reactivity to cow’s milk or yeast gives you a focused starting point for a trial elimination. If migraine frequency falls during the elimination, you have a strong lead to discuss with your GP or nutritionist.
Scenario 2: The Dairy Dilemma
Many people assume they have a dairy problem and switch to lactose-free milk. If symptoms persist, it may be the milk proteins (whey or casein), not lactose. Lactose intolerance is an enzyme issue; protein sensitivity is immune-mediated. A sensitivity test that flags milk proteins helps you decide whether full dairy avoidance, alternative milks, or another strategy is appropriate.
Implementing Your Results (The Reintroduction Phase)
Whether you use an MRT result or a Smartblood IgG report, the data is only the beginning. The real progress happens during the elimination and reintroduction phase.
Key Takeaway: You should never simply cut out dozens of foods forever based on a test result. This can lead to nutritional deficiencies and a poor relationship with food.
We recommend a 4-phase plan:
- Elimination Phase (4–6 weeks): Remove the high-reactivity foods completely.
- Observation Phase: Monitor symptoms carefully.
- Structured Reintroduction: Introduce one food at a time, every three days, to confirm reactions.
- Maintenance: Decide which foods to avoid, limit, or reintroduce regularly.
For a clear, practical explanation of reading results and reintroduction timing, our guide on reading food intolerance test results is a useful resource.
The LEAP Diet vs. The Smartblood Approach
If you undergo an MRT test, you may be guided towards the LEAP (Lifestyle Eating and Performance) diet, a prescriptive protocol that uses MRT data to build an "immunocalm" diet starting with least-reactive foods.
At Smartblood, our approach shares the same principle—start with the lowest-risk foods and reintroduce carefully—but we focus on empowering you with a clear 0–5 scale and supporting materials so you can manage reintroduction alongside your GP or a qualified nutritionist.
Our panel of 260 foods gives a wide lens on less-obvious ingredients that might otherwise be missed.
Why Choose Smartblood?
We understand you have options for testing. At Smartblood, we focus on trust, clarity and support.
- GP-led heritage — we complement, not replace, NHS care.
- Easy home finger-prick kit — no clinic visit required.
- Fast turnaround — priority results usually within 3 working days of our lab receiving your sample.
- Actionable reporting — a 0–5 reactivity scale and practical guidance, not just a list.
If you want to see the tests we offer, our collection of all blood tests lists the Food Intolerance Test and related options. If you have specific concerns before ordering, please contact us and our team will be happy to help.
Our Food Intolerance Test is priced at £179.00 for the comprehensive kit covering 260 foods, and code ACTION may be available for 25% off at checkout; check the product page for current offers and to purchase the kit.
Conclusion
The journey to resolving "mystery symptoms" can be long and tiring. Whether you are exploring MRT or an IgG-based test like ours, the aim is the same: to identify which foods are contributing to chronic, low-grade inflammation. MRT offers an interesting functional view of mediator release, while IgG panels provide a standardised antibody map that integrates neatly into a structured elimination and reintroduction plan.
Remember: GP first, diary and elimination second, testing third. Used thoughtfully, testing is a powerful tool to reduce guesswork and help you rebuild a comfortable, enjoyable diet.
If you’d like to learn more about the studies that inform our approach, visit our Scientific Studies hub — and if you have questions, we’re here via the Smartblood contact page.
FAQ
Is the MRT food sensitivity test the same as an allergy test?
No. The MRT is not an allergy test. It does not measure IgE antibodies, which are responsible for immediate, potentially life-threatening allergic reactions. MRT is designed to identify food sensitivities and intolerances that cause delayed, inflammatory symptoms. If you suspect you have a severe food allergy, you must consult your GP or an allergist for IgE testing and carry appropriate medication as advised.
How does the MRT differ from the IgG testing used by Smartblood?
While both tests aim to identify food-related immune activity, they measure different things. MRT measures mediator release by observing white blood cell changes. Smartblood’s test measures IgG antibody concentrations using ELISA and reports results on a 0–5 reactivity scale to help you prioritise foods for elimination. If you are considering testing, you can order the Smartblood Food Intolerance Test online.
Can I get an MRT or food sensitivity test on the NHS?
The NHS typically focuses on testing for food allergies (IgE), coeliac disease, and specific enzyme deficiencies like lactose intolerance. Tests such as MRT or IgG food sensitivity panels are generally not provided by the NHS and are offered through private providers. If you’re unsure whether testing is appropriate for you, check our FAQ for practical details or contact Smartblood directly.
Do I have to stop eating certain foods forever after a test?
Absolutely not. The goal of any sensitivity test is to guide a temporary elimination trial. After 4–6 weeks you should begin structured reintroduction to find your personal thresholds. Many people can reintroduce foods in moderation once inflammation has settled. If you need help interpreting your results or planning reintroduction, our read-results guide and support team can help.
