Table of Contents
- Introduction
- Understanding the Difference: Allergy vs. Intolerance
- How to Get Tested for Lactose Intolerance
- How to Get Tested for Gluten Intolerance
- The Smartblood Method: A Phased Approach
- What is IgG Testing?
- Practical Scenarios: Is It Lactose, Gluten, or Something Else?
- How the Smartblood Test Works
- Managing Your Results and Diet
- Why Choose Smartblood?
- Conclusion
- FAQ
- Medical Disclaimer
Introduction
It is a familiar scene for many in the UK: a Friday night takeaway or a Sunday roast followed, like clockwork, by a familiar sense of dread. For some, it is the sharp, cramping pain that follows a bowl of pasta; for others, it is the heavy, foggy exhaustion that sets in after a latte. You might find yourself searching for the nearest pharmacy for antacids or cancelling plans because the bloating makes your favourite jeans feel two sizes too small.
When these "mystery symptoms" become a regular feature of your life, it is natural to look for a culprit. Usually, two names sit at the top of the list: lactose and gluten. But knowing how to get tested for lactose and gluten intolerance isn't always straightforward. With a mix of NHS pathways, home kits, and differing medical opinions, many people feel overwhelmed before they even begin.
At Smartblood, we believe that true well-being comes from understanding your body as a whole, rather than just chasing isolated symptoms. In this article, we will walk you through the clinically responsible journey of investigating these sensitivities. We will explore the medical tests available through your GP, the difference between an allergy and an intolerance, and how a Smartblood Food Intolerance Test can act as a targeted snapshot to guide your dietary choices once medical causes have been ruled out.
Our thesis is simple: your health journey should always start with your GP to rule out underlying conditions. From there, a structured approach involving symptom tracking and guided elimination is the most effective way to regain control.
Understanding the Difference: Allergy vs. Intolerance
Before we dive into the specific tests, we must clarify a common point of confusion. Many people use the terms "allergy" and "intolerance" interchangeably, but in the world of biology, they are very different.
What is a Food Allergy?
A food allergy is an immune system reaction. Specifically, it usually involves IgE (Immunoglobulin E) antibodies. When someone with an allergy eats the trigger food, their immune system overreacts, releasing chemicals like histamine. This usually happens very quickly—often within minutes.
Symptoms can include hives, itching, or swelling of the lips and face. In severe cases, it can lead to anaphylaxis, which is a life-threatening emergency.
Urgent Safety Warning: If you or someone else experiences swelling of the lips, tongue, or throat, difficulty breathing, wheezing, a sudden drop in blood pressure, or collapse, call 999 or go to A&E immediately. These are signs of a severe allergic reaction, and food intolerance testing is not appropriate for these scenarios.
What is a Food Intolerance?
A food intolerance (or sensitivity) is generally not life-threatening, but it can be life-disrupting. It typically involves the digestive system rather than a rapid IgE immune response.
Symptoms like IBS and bloating often appear hours or even days after eating the food. This delay makes it incredibly difficult to identify the culprit through guesswork alone. While the NHS focuses on diagnosing specific conditions like coeliac disease or primary lactose intolerance, many people fall into a "middle ground" where they feel unwell despite clear medical tests.
To understand more about these distinctions, you can read our guide on food allergy vs food intolerance.
How to Get Tested for Lactose Intolerance
Lactose is a type of sugar found naturally in milk and dairy products. To digest it, your body needs an enzyme called lactase, produced in the small intestine. If you don't produce enough lactase, the lactose passes undigested into your colon, where bacteria ferment it, leading to gas, diarrhoea, and pain.
Step 1: The GP Consultation
If you suspect dairy is the problem, your first port of call should be your GP. They will want to rule out other causes for your digestive distress, such as Inflammatory Bowel Disease (IBD) or infections.
Step 2: The Hydrogen Breath Test
This is the most common clinical test for lactose intolerance in the UK. During the test, you drink a liquid containing a high concentration of lactose. You then breathe into a balloon-like container at regular intervals (usually every 30 minutes for a few hours).
If you aren't digesting the lactose, the bacteria in your gut will produce hydrogen gas, which is absorbed into your blood and exhaled. High levels of hydrogen in your breath suggest lactose malabsorption.
Step 3: The Glucose Blood Test
Less common but still used, this involves measuring the amount of glucose (sugar) in your blood after consuming lactose. If your body is breaking down lactose correctly, your blood sugar levels should rise. If they don't, it may indicate that your body isn't processing the lactose into glucose.
The Self-Elimination Trial
Your GP might also suggest a "milk challenge" or an elimination diet. This involves removing all dairy and eggs from your diet for a set period, usually two weeks, to see if symptoms resolve, then reintroducing them to see if they return.
How to Get Tested for Gluten Intolerance
Gluten is a protein found in wheat, barley, and rye. Investigating gluten is more complex because it involves distinguishing between an autoimmune disease and a sensitivity.
Testing for Coeliac Disease (The Priority)
Before you stop eating gluten, you must be tested for coeliac disease. This is a serious autoimmune condition where the immune system attacks the lining of the small intestine when gluten is consumed.
The standard NHS pathway involves:
- Blood Test: Looking for specific antibodies (tTG-IgA). You must be eating gluten regularly (at least one meal a day for six weeks) for this test to be accurate.
- Biopsy: If the blood test is positive, a gastroenterologist may perform an endoscopy to take a small tissue sample from the small intestine to check for damage (villi atrophy).
It is vital to note that a Smartblood Food Intolerance Test does not diagnose coeliac disease.
Non-Coeliac Gluten Sensitivity (NCGS)
If your coeliac tests come back negative, but you still experience fatigue, bloating, or joint pain after eating bread or pasta, you may have Non-Coeliac Gluten Sensitivity.
Currently, there is no single "official" NHS test for NCGS. It is usually diagnosed through a process of elimination under the guidance of a dietitian or GP. You can learn more about how wheat impacts the body in our section on gluten and wheat.
The Smartblood Method: A Phased Approach
At Smartblood, we don't believe in testing as a "first resort." We advocate for a phased, clinically responsible journey that puts you in the driving seat of your own health.
Phase 1: Rule Out the "Red Flags"
Always see your GP first. If you are experiencing unexplained weight loss, blood in your stools, or severe, persistent pain, these require urgent medical investigation to rule out serious conditions.
Phase 2: Track and Eliminate
Before spending money on tests, try to identify patterns. We provide a free food elimination diet chart to help you record what you eat and how you feel.
For many people, a simple diary reveals the culprit. For instance, if you notice that your migraines only occur on days you've had a specific type of bread or a certain drink, you have a clear starting point for a trial elimination.
Phase 3: Targeted Testing
If you have seen your GP, ruled out coeliac disease and other conditions, and tried a basic elimination diet but are still feeling "stuck," this is where the Smartblood Food Intolerance Test can help.
Instead of guessing which of the hundreds of foods in your diet might be the problem, our test looks for IgG antibodies against 260 different foods and drinks.
What is IgG Testing?
IgG (Immunoglobulin G) is a type of antibody that the body produces in response to various triggers, including food. While IgE is linked to immediate allergies, IgG is often associated with delayed responses.
It is important to be transparent: the use of IgG testing to identify food intolerances is a subject of ongoing debate in the medical community. Some experts believe IgG is simply a marker of "food exposure"—meaning you have antibodies to things you eat often.
At Smartblood, we frame IgG testing differently. We see it as a tool to help guide a structured elimination and reintroduction plan. Think of it as a "snapshot" of your immune system's current conversation with your diet. By identifying which foods are showing high reactivity on a 0–5 scale, you can prioritise which foods to remove first, making the elimination process much less daunting.
For those interested in the underlying data, we maintain a hub of scientific studies that explore how IgG-guided diets have helped individuals with conditions like IBS and migraines. You can read more about unmasking food sensitivities on our blog.
Practical Scenarios: Is It Lactose, Gluten, or Something Else?
Identifying a food trigger is rarely as simple as "I ate X, and now Y is happening." Here are a few common scenarios our customers face:
Scenario A: The "Healthy" Smoothie
You’ve switched to a healthy morning routine: a smoothie with protein powder, fruit, and almond milk. Yet, you feel more bloated than ever. Is it the fruit (fructose), the protein (whey/dairy), or perhaps a sensitivity to fruits like kiwi or strawberry?
Without testing, you might cut out dairy only to find the bloating remains because the true culprit was a specific fruit or a sweetener in the protein powder.
Scenario B: The Sunday Roast
You feel terrible after a Sunday roast. You suspect the Yorkshire puddings (gluten), but it could just as easily be the yeast in the gravy, the vegetables, or even the wine you drank with the meal.
A structured test can help you distinguish between a broad intolerance to gluten and a specific reaction to a single ingredient, preventing you from unnecessarily restricting your diet.
Scenario C: The "Lactose-Free" Struggle
You have already switched to lactose-free milk, but your skin problems and digestive issues persist. This is a common situation. Lactose intolerance is about the sugar in milk, but you might actually be reacting to the proteins (whey or casein) in the milk. In this case, even lactose-free dairy will cause a reaction. Understanding this distinction is vital for long-term relief.
How the Smartblood Test Works
If you decide that you want a clearer picture of your food reactivities, our process is designed to be simple and supportive.
- Order Online: You can purchase the Smartblood Food Intolerance Test for £179.00.
- Home Collection: We send you a finger-prick blood kit. You collect a small sample of blood from the comfort of your home and post it back to our accredited lab in the prepaid envelope.
- Laboratory Analysis: Our lab uses ELISA technology to measure IgG antibodies against 260 food and drink ingredients.
- Results: You will typically receive your priority results via email within 3 working days of the lab receiving your sample.
- Support: Your results include a clear 0–5 scale of reactivity. We don't just leave you with a list of "bad" foods; we provide guidance on how to use these results to inform your conversations with your GP or a nutritionist.
To see a full list of what we test for and how the process looks, visit our How it Works page.
Managing Your Results and Diet
Receiving a list of reactive foods can be daunting. The goal is not to stop eating everything on the list forever. Instead, the results should be used to:
- Prioritise an Elimination: Remove the most highly reactive foods for a period of 4–6 weeks.
- Monitor Symptoms: Use your diary to see if your feeling of sluggishness or bloating improves.
- Structured Reintroduction: Gradually reintroduce foods one by one to see which ones your body can tolerate in small amounts and which ones are true "trigger" foods.
Many people find that once they have calmed their system down by removing high-reactivity foods, they can eventually tolerate those foods again in moderation. It is about finding your body's unique threshold.
Why Choose Smartblood?
Smartblood was founded with a mission to help people access reliable information about their health in a non-salesy, informative way. We understand the frustration of living with "mystery symptoms" that don't always fit into a neat medical box.
Our Our Story reflects our commitment to a GP-led approach. We don't want to replace your doctor; we want to give you the data you need to have a more productive conversation with them. Whether you are looking for weight gain solutions related to malabsorption or fitness optimisation, understanding your intolerances is a powerful first step.
Conclusion
Determining how to get tested for lactose and gluten intolerance is the beginning of a journey toward better health. It is a path that requires patience, a structured approach, and, most importantly, professional medical guidance.
To recap the Smartblood Method:
- See your GP first. Rule out coeliac disease, IBD, and other medical conditions.
- Start a diary. Use our free resources to track your symptoms and identify potential patterns.
- Try a simple elimination. See if removing obvious culprits like dairy or wheat helps.
- Consider testing. If you are still struggling to identify triggers, use the Smartblood test as a comprehensive "snapshot" to guide your next steps.
By following this phased approach, you avoid the trap of "chasing symptoms" and instead build a foundation of understanding based on your body's unique biological responses.
If you are ready to move away from guesswork and towards a clearer understanding of your diet, the Smartblood Food Intolerance Test is available for £179.00. While we cannot guarantee a "cure" for your symptoms, we can provide the data you need to make better-informed choices about the food you eat every day. If you have any questions about the kit, medications, or the process, please visit our FAQ or Contact us directly.
Currently, the discount code ACTION may be available on our site to give you 25% off your order.
FAQ
Can I take a food intolerance test if I am already on a gluten-free diet? For the Smartblood IgG test, we look for antibodies your body has produced. If you have not eaten a specific food (like gluten) for several months, your antibody levels may have dropped, which could lead to a lower reactivity result. However, for a coeliac disease blood test through your GP, you must be eating gluten for the results to be accurate.
Is lactose intolerance the same as a milk allergy? No. Lactose intolerance is a digestive issue where you lack the enzyme to break down milk sugar. A milk allergy is an immune system reaction to the proteins in milk. A milk allergy can be severe and rapid, whereas lactose intolerance usually causes digestive discomfort a few hours later.
How long does it take to see results after changing my diet? While some people feel better within a few days, it typically takes 4 to 6 weeks for the body's inflammatory response to settle down after removing a trigger food. This is why we recommend a structured elimination period before beginning the reintroduction phase.
Do I need a GP's referral to take a Smartblood test? No, you can order the test directly from us. However, we strongly recommend that you consult your GP before making any significant dietary changes or if you are experiencing "red flag" symptoms. Our results are designed to be shared with health professionals to help guide your care.
Medical Disclaimer
The information provided in this article is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the advice of your GP or another qualified health provider with any questions you may have regarding a medical condition. The Smartblood Food Intolerance Test is an IgG-based test that can help guide a structured elimination diet; it is not an allergy test and does not diagnose IgE-mediated allergies or coeliac disease. If you experience symptoms of a severe allergic reaction, such as swelling of the lips, tongue, or throat, or difficulty breathing, seek urgent medical attention immediately by calling 999 or attending A&E.
