Diagnostic testing
Food Sensitivity Test (FST)
When digestion feels off or inflammation lingers, food sensitivities may be part of the picture.
The Food Sensitivity Test is a saliva-based assessment evaluating IgA and IgG immune responses to commonly consumed foods.
It is particularly useful for identifying delayed sensitivities that may contribute to digestive discomfort, inflammation, fatigue, and weight loss resistance, and for clarifying how immune reactions to food may be affecting gut health.
PhotographyFood Sensitivity Test collection kit, laid out on a clean surface.
What it measures
Inside the FST
IgA response
The antibody most associated with mucosal and gut-level immune activity.
IgG response
Associated with delayed reactions, which can appear hours or days after eating.
A panel of common foods
Covering the items most often involved in delayed sensitivity patterns.
Who this test is for
It may be a fit if you are experiencing
- Bloating, gas, or digestive discomfort
- Inflammation that lingers without explanation
- Fatigue after eating
- Skin changes or congestion
- Weight loss resistance
- Symptoms that do not seem connected to what you are eating
Why saliva
What saliva shows that a single blood draw cannot
Saliva reflects mucosal immune activity, which is where food first meets the immune system. Collection is non-invasive and done at home.
The lab we use has been trusted for decades by our pharmacist and master of holistic medicine, particularly for complex hormone cases. The methodology is well established, reproducible, and clinically actionable.
How results are used at LivBTR
Your results are never read in isolation
They are interpreted alongside your intake, symptoms, lifestyle, nutrition, movement, and any other findings. From there we build a personalized support plan.
- A structured, temporary elimination and reintroduction plan
- Gut support strategies alongside removal
- Nutrition planning that keeps your diet varied rather than restrictive
- Supplement protocols when appropriate
- A retest conversation once the gut has had time to settle
The aim is a short, structured period of change followed by planned reintroduction.
Food Sensitivity Test questions
Is this the same as a food allergy test?
No, and the difference matters. Allergy testing looks at IgE-mediated reactions, which can be immediate and severe. This looks at IgA and IgG patterns associated with delayed sensitivity. If you have a diagnosed allergy, that remains a medical matter.
How is the test collected?
A saliva sample collected at home using the provided kit.
Can food sensitivities affect weight or hormones?
They can contribute. Ongoing low-grade inflammation and digestive disruption influence energy, sleep, cravings, and how your body handles the same food.
Will I need to avoid foods forever?
Usually not. The typical approach is a temporary, structured removal followed by planned reintroduction, alongside work on gut health.
Can stress affect results?
Yes. Stress affects gut permeability and mucosal immunity, which is one reason results are read alongside your wider picture rather than alone.
Do medications or supplements affect results?
Some can, particularly steroids and immune-modulating medication. Instructions come with your kit.
If digestion, energy, or inflammation has been a persistent problem, this narrows down where to look.
The goal is a varied diet you can live with, not a shorter list of foods.