Blood Test Shows IgG Levels: Guide for Allergy Testing

The blood test that shows IgG levels is the IgG antibody test, typically ordered as part of a food sensitivity panel. Also known as immunoglobulin G testing, this blood draw measures your body’s delayed immune response to various foods and substances. Unlike immediate IgE reactions, IgG responses can appear hours or days after exposure, helping identify chronic inflammation and digestive issues. This guide from allergypanels.com explains everything you need to know about IgG testing, from what it measures to how to order your own panel.

Understanding IgG and Its Role in Allergies

What Is Immunoglobulin G?

Immunoglobulin G (IgG) is the most abundant antibody in your bloodstream, comprising about 75% of serum antibodies. It is produced by plasma cells as part of the adaptive immune system. While IgE triggers immediate allergic reactions (e.g., hives, anaphylaxis), IgG is associated with delayed hypersensitivity – symptoms like fatigue, brain fog, bloating, joint pain, and skin issues that surface 24 to 72 hours after exposure. Testing IgG levels helps identify food sensitivities that conventional allergy tests may miss.

IgG vs. IgE: Key Differences

Many patients confuse IgG testing with traditional IgE allergy tests. IgE tests detect immediate, potentially life-threatening allergies (e.g., peanuts, shellfish). In contrast, IgG tests reveal delayed immune reactions that often contribute to low-grade chronic inflammation. An IgG blood test shows levels for dozens of foods, additives, and environmental factors, enabling a targeted elimination diet. At allergypanels.com, we provide comprehensive IgG panels that include up to 200+ items, using ELISA technology for precision.

What Does an IgG Blood Test Measure?

An IgG blood test quantifies the concentration of IgG antibodies against specific antigens. The most common type is the food-specific IgG panel, which screens for immune reactivity to:

• Dairy (milk, cheese, yogurt)
• Grains (wheat, gluten, corn, rice)
• Proteins (egg white, egg yolk, beef, chicken, pork)
• Seafood (salmon, shrimp, tuna, cod)
• Fruits and vegetables (apple, tomato, spinach, citrus)
• Nuts and seeds (almond, peanut, sunflower)
• Spices and herbs (garlic, ginger, oregano)
• Additives (food colorings, preservatives)

Results are typically reported in units per milliliter (U/mL) and categorized as normal, borderline, or elevated. Some advanced panels also measure IgG4 subclass, which can indicate tolerance or ongoing exposure.

How to Interpret Your IgG Levels

Interpreting IgG results requires understanding reference ranges. Below is a sample table showing typical interpretation categories used by laboratories today:

IgG Level (U/mL)	Interpretation	Recommendation
< 10	Normal – no reactivity	Continue consumption as tolerated
10–30	Borderline – mild reactivity	Consider rotation diet
31–100	Elevated – moderate reactivity	Eliminate for 4–6 weeks, then challenge
> 100	High – significant reactivity	Remove from diet for 90 days

Note: Reference ranges may vary by lab. Always consult a healthcare provider before making dietary changes. Elevated IgG levels do not necessarily indicate a disorder – they represent a marker of immune exposure. At allergypanels.com, every result includes a personalized guide for elimination and reintroduction.

When Should You Consider an IgG Blood Test?

An IgG blood test is most useful for individuals experiencing chronic, vague symptoms that standard allergy tests fail to explain. Common triggers include:

• Unexplained fatigue or brain fog
• Digestive issues (bloating, gas, IBS-like symptoms)
• Recurrent headaches or migraines
• Joint or muscle pain without injury
• Skin conditions (eczema, acne, rashes)
• Weight loss resistance or cravings

Because IgG reactions are delayed, many people overlook the connection between their diet and symptoms. Testing provides objective data to guide an elimination diet, often leading to significant improvements in quality of life.

How to Order an IgG Test from allergypanels.com

Getting your IgG levels measured has never been easier. At allergypanels.com, we offer CLIA-certified home blood draw kits for IgG food sensitivity panels. Your sample is processed in a US-based laboratory, and results are delivered directly to your secure online account within 7–10 business days. No doctor visit required – simply order your preferred panel, collect a small blood sample using the lancet provided, and mail it back with the prepaid envelope. For those who prefer in-lab draws, we also partner with thousands of patient service centers nationwide.

Ready to discover what your IgG levels reveal? Order your IgG panel today and take the first step toward understanding your body’s hidden reactions.