Food Sensitivity Testing
Food reactions require careful distinction between allergy, intolerance and other symptoms. Food IgG panels do not diagnose food allergy and are not validated to diagnose food intolerance or sensitivity. AAAAI recommends against using them for these purposes; an offered test should be discussed transparently, including these limitations.
What does an IgG result mean?
Antibodies to foods can reflect exposure rather than a harmful reaction. A positive panel result is not a reason to label every listed food unsafe or to remove large parts of a balanced diet. If the practice discusses this testing, ask what evidence supports the proposed use and whether a better-established evaluation would answer your concern.
When is an allergist needed?
Immediate hives, lip or tongue swelling, wheezing or collapse after food can indicate allergy. Breathing difficulty or collapse is an emergency. An allergist selects testing from the reaction history; do not attempt home challenges after a serious reaction or use a sensitivity panel to exclude allergy.
Safer nutrition discussions
Review a symptom-and-food diary with a qualified clinician or dietitian. Any elimination and reintroduction approach needs a defined purpose, nutritional adequacy and a follow-up plan. Suspected celiac disease deserves its own diagnostic pathway before gluten avoidance.
What different tests can and cannot answer
| Clinical question | Possible starting point | Important limitation |
|---|---|---|
| Is thyroid function abnormal? | TSH, with free T4 as appropriate | Interpretation depends on context, medicines and pregnancy. |
| Is autoimmunity involved? | Selected thyroid antibody tests | Positive antibodies do not establish the degree of hormone deficiency. |
| Is there a structural lump? | Examination and ultrasound, with specialist assessment | Normal hormone tests do not exclude an important nodule. |
| Does a food cause allergy? | Reaction history and appropriately selected allergist testing | A food IgG panel cannot diagnose or exclude allergy. |
| Are stress symptoms an adrenal disease? | Medical history and validated testing when indicated | “Adrenal fatigue” is not an established diagnosis. |
Questions and answers
What does an IgG result mean?
Antibodies to foods can reflect exposure rather than a harmful reaction. A positive panel result is not a reason to label every listed food unsafe or to remove large parts of a balanced diet. If the practice discusses this testing, ask what evidence supports the proposed use and whether a better-established evaluation would answer your concern.
What should I know about safer nutrition discussions?
Review a symptom-and-food diary with a qualified clinician or dietitian. Any elimination and reintroduction approach needs a defined purpose, nutritional adequacy and a follow-up plan. Suspected celiac disease deserves its own diagnostic pathway before gluten avoidance.
Sources and further reading
- American Thyroid Association: Thyroid hormone treatment
- American Thyroid Association: Hashimoto’s thyroiditis
- NIDDK: Thyroid tests
- American Thyroid Association: Thyroid function tests
- NIDDK: Hashimoto’s disease
- NIDDK: Graves’ disease
- American Thyroid Association: Thyroid nodules
- Endocrine Society: Adrenal fatigue
- AAAAI: Limits of food IgG panel testing
- NIDDK: Diagnosis of celiac disease
- American Thyroid Association: Hypothyroidism during pregnancy
Educational information only, not medical advice, diagnosis or a treatment plan. Do not stop, start or change prescribed medication based on this resource. Pregnancy, children, significant heart symptoms and complex endocrine disease require appropriate medical care. Seek emergency help for chest pain, severe breathing difficulty, fainting, or high fever with confusion and a very fast heartbeat. A discovery call is not urgent medical care.