Why IgG Food Allergy Testing Fails – Allergy vs Intolerance Explained
A patient confidently walks into the clinic. She has a beautiful binder in hand.
“Doc, look!” she waves at her IgG food allergy testing results, all lit up in green, yellow, and red.
“I can’t eat any of these foods!”
I peer over the report and ask:
- “Swollen eyes or hives?”
- “Itching or throat tightness?”
- “Shortness of breath?”
Silence. “None,” she admits.
“So… no true allergy,” I say gently.
Her shoulders slump. “Fine—then I guess I’m intolerant. But I cut them all out, and I still feel lousy!”
If this sounds familiar, you’re in the right place. Let’s dive into why IgG food allergy testing often misleads—and how to pinpoint real triggers instead.
Why IgG Food Allergy Testing Confuses Patients
IgG⁼Exposure Marker, Not Allergy. A positive IgG just means you’ve eaten that food—nothing about a harmful reaction. AAAAI
False Positives Go Wild. Healthy folks often show IgG to staples like milk or rice—and keep eating them with zero issues.
Useless Elimination Diets. Dropping dozens of foods based on IgG panels can backfire—nutrient gaps, social stress, and… still feeling unwell. PubMed
Food Allergy vs. Food Intolerance—The Quick Guide
Food Allergy (IgE-Mediated)
Imagine a bomb explosion with a huge bang! That’s an IgE allergy for you—symptoms like hives, swelling, or wheezing can erupt within minutes of eating the trigger food. To pin these down, we rely on:
Skin Prick Tests – A tiny scratch, a drop of allergen, and you’ve got your answer within 15 minutes.
Specific IgE Blood Tests – A simple blood draw that measures your allergic antibodies.
Supervised Oral Food Challenges – The gold standard, done under medical watch to confirm real-world reactions.
Food Intolerance (Non-Allergic)
Think of this as a digestion and gut processing problem. Symptoms—bloating, cramps, diarrhea—often sneak up hours after that plate of pasta or latte. Common culprits include:
Enzyme Shortages (e.g., lactose intolerance when your body can’t break down milk sugar)
Chemical Irritants (e.g., spicy food causing stomach cramps and diarrhea)
How do you sort it out?
History & Elimination: Ditch the suspect item for a week or two and see if you feel better.
Optional Breath Tests: For lactose (hydrogen breath test) or fructose, this can confirm malabsorption.
By keeping food allergies and intolerances straight—rapid IgE reactions versus delayed enzyme or irritant issues—you’ll know exactly which tests to ask for and which foods to avoid, without the guesswork (or the confusing IgG panels!).
Real-World Example: Lactose Intolerance in Asians
Did you know that more than 70% of Asians lose the lactase enzyme after childhood? That means milk or ice cream might leave you gassy and bloated.
No Fancy IgG Test Needed. Your symptoms + a simple two-week dairy break tell the story.
Optional Confirm: A lactose hydrogen breath test can seal the deal.
How to Diagnose True Food Reactions
Keep a Food Diary: Write down what you eat and how you feel.
Choose the Right Tests:
Allergy: Skin prick or specific IgE → supervised food challenge.
Intolerance: Elimination diet → breath test if needed for lactose intolerance.
Reintroduce Foods One at a Time: Confirm your genuine triggers.
Next Steps: Swap Confusion for Clarity
Ditch the IgG Binder. Save the binder for your vacation photos.
Book a Real Consultation. Let’s use proven tests and your own story to find true triggers.
Eat with Confidence. Know exactly which foods to avoid—and which you can enjoy without fear.
Don’t let flashy charts rule your life. With the right history, targeted tests, and expert guidance, you’ll reclaim your kitchen—and your peace of mind.
📌 Ready for clarity? 👉 Contact the Allergy Immunology Clinic today!
