Food Sensitivity & Allergy Testing in Lisle, IL | Defiant Health
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Lisle, IL

Diagnostic Testing

Comprehensive food sensitivity panels, allergy testing, and combo panels to inform your nutrition and protocol decisions. Serving Lisle, Naperville & Chicago’s western suburbs.

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About Diagnostic Testing

What Is Diagnostic Testing at Defiant?

Defiant offers a focused set of diagnostic panels designed to inform nutrition and protocol decisions: IgG-based food sensitivity testing, IgE-based allergy testing, and a combination panel that covers both. Each is a blood-based test. We can write the order and review your results; the draw itself is done through your PCP or Rythm Health. Results return in 1 to 2 weeks.

Why Clients Test
  • + Inform weight loss and peptide protocols
  • + Starting point for elimination diets
  • + Identify classic environmental allergens
  • + Comprehensive results in 1 to 2 weeks
  • + Provider walkthrough of results included

How Our Diagnostic Panels Work

Food Sensitivity Panel (IgG)

A broad IgG panel covering common foods. Honest framing: IgG testing is debated in the literature, so we use it as a starting point for elimination work, not as a diagnosis. Best for low-grade chronic symptoms.

Allergy Test (IgE)

The classic IgE allergy test. Measures the immune pathway behind hives, swelling, hay fever, and acute allergic reactions. Well-established methodology with clear clinical use.

Combo Panel (IgG + IgE)

Both IgG and IgE in a single draw. Useful when you suspect a mix of classic allergies and lower-grade food triggers, or as the broadest starting point before a weight loss or peptide protocol.

Blood Draw & Lab

We write the order, you complete the draw through your PCP or Rythm Health. Results return in 1 to 2 weeks and we walk through them with you to plan elimination, reintroduction, or referral.

What Diagnostic Testing Can Support

These panels matter most when they change a decision. Done in isolation, a panel is just a list of foods. Done in the context of a weight loss, peptide, or recovery protocol, the same panel can shape your nutrition plan and the cadence of follow-up. Common use cases:

  • + Inform nutrition before a weight loss protocol
  • + Starting point for elimination and reintroduction work
  • + Identify environmental allergens behind chronic symptoms
  • + Inform peptide protocol design
  • + Reduce chronic inflammatory load on the gut
  • + Document baseline before bigger nutrition changes

Considering testing? Bring your symptom list and goals to your appointment. We’ll recommend the panel that fits, and skip the ones that don’t.

Diagnostic panels at Defiant are informational. They are not a substitute for medical diagnosis or allergy management by a board-certified specialist.

Diagnostic Panels

Blood-based panels. Draw completed through your PCP or Rythm Health. Results in 1 to 2 weeks.

Food Sensitivity Panel
$300
IgG · 250 Foods

Identifies foods that may be causing chronic discomfort like bloating, headaches, fatigue, or digestive issues. Measures your immune response to 250 common foods.

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Most Comprehensive
Combo Panel
$400
IgG + IgE · 250 Markers

The full picture. Combines the Food Sensitivity and Allergy panels into one comprehensive report covering both foods and environmental triggers in a single draw.

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Allergy Test
$200
IgE · 150 Allergens

Pinpoints environmental and seasonal allergens behind sneezing, congestion, itchy eyes, and sinus issues. Pollen, pet dander, mold, and more.

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Common Questions

Everything you need to know about food sensitivity, allergy, and combo diagnostic panels at Defiant in Lisle, IL, serving Naperville and Chicago’s western suburbs.

An allergy test measures IgE antibodies, which are the immune response behind classic allergic reactions like hives, swelling, or anaphylaxis. A food sensitivity test measures IgG antibodies, which reflect exposure and immune reactivity but don’t cause the same acute response. IgE testing is well established. IgG testing is debated in the medical literature: we present it as informational input, not a diagnostic.
Honest answer: IgG-based food sensitivity testing is debated. Many mainstream allergy bodies note that IgG antibodies often reflect normal exposure to foods rather than a true sensitivity. We use it as a starting point for elimination-and-reintroduction work, not as a diagnosis. If you want a more conservative approach, an elimination diet without testing is a valid option.
If you suspect classic allergies (hay fever, environmental triggers, food-allergic reactions), the IgE Allergy Test is the right starting point. If you suspect that specific foods are driving low-grade symptoms (bloat, fatigue, skin issues, brain fog), the IgG Food Sensitivity Panel can inform elimination work. The Combo Panel covers both.
Both are blood-based panels. The draw is done in-clinic. Results typically come back in 1 to 2 weeks, and we walk through them with you to plan next steps, including elimination, reintroduction, or referral if needed.
Persistent inflammation from undetected food triggers can make weight loss harder, blunt energy, and complicate peptide protocols. Identifying and addressing triggers often makes the rest of a weight loss protocol work better. We pair testing with protocol decisions, not as a standalone.
Most clients pay out of pocket. Some panels may be reimbursable through HSA or FSA. We don’t bill insurance directly for these panels, ask us for the receipt format if you plan to submit for reimbursement.
Pricing is discussed at your appointment so we can recommend the panel that fits your actual symptoms and goals rather than upselling the most comprehensive option by default.
Defiant is located at 5100 Lincoln Ave, Lisle, IL 60532, serving Naperville, Downers Grove, Wheaton, Bolingbrook, Lombard, and the western Chicago suburbs.

Data Before Decisions

Bring your symptom list and your goals. We’ll match the panel to what you’re actually trying to learn. Diagnostic testing at Defiant in Lisle, IL.

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