IgG4 Foodscreen (Biovis)

Identifies delayed food sensitivities by measuring IgG4 antibody response to a panel of common foods

IgG4 Foodscreen (Biovis)

Table of contents

Basic data

The IgG4 Foodscreen test analyzes the presence of specific IgG4 antibodies against a wide range of common dietary proteins. Elevated IgG4 levels may indicate delayed food sensitivities — a distinct phenomenon from immediate allergic reactions (IgE-mediated).

This test is often used to guide elimination diets for individuals with chronic symptoms such as gastrointestinal discomfort, skin issues, migraines, or fatigue when no other clear cause is found.

Category: Lab blood panel

Level: Intermediate

Usefulness: Medium

Level

Intermediate

This test is most useful for intermediate-level users who have already addressed fundamental lifestyle pillars such as nutrition quality, sleep, and physical activity — and are now exploring hidden or functional contributors to chronic symptoms.

Usefulness

Medium

IgG4-based food sensitivity testing remains debated in conventional medicine, but it may provide practical value when used as part of a structured elimination and reintroduction protocol.
Identifies delayed food sensitivities

Highlights potential culprits in chronic digestive, neurological, or dermatological complaints — especially when traditional allergy testing is negative.

Supports targeted elimination diets

Allows users to temporarily eliminate foods with high IgG4 reactivity and observe symptom changes, potentially clarifying hidden dietary triggers.

How it works

The test involves a blood draw analyzed for IgG4-class antibodies specific to a panel of 44, 90, or more food antigens, depending on the test variant.
Sample collection

A venous blood sample is taken and sent to the laboratory, where serum IgG4 levels against food antigens are measured.

Result interpretation

The report highlights foods with elevated antibody levels, suggesting past exposure and potential sensitivity. Color-coded graphs are often used.

Measures

The IgG4 Foodscreen assesses immune reactivity to common dietary proteins.
IgG4 antibody titers

Quantifies the level of food-specific IgG4 antibodies — a marker of delayed immune response.

Reactivity scores (low/moderate/high)

Categorizes foods into reactivity zones, guiding dietary elimination priorities.

Reliability

IgG4 testing is controversial in evidence-based medicine due to limited standardization and variable reproducibility, but may still offer directional guidance.
High variability between individuals

Immune response patterns differ significantly between people and are influenced by food frequency, gut integrity, and immune status.

Not diagnostic of allergy

IgG4 levels do not indicate immediate allergies or anaphylaxis risk — only delayed or tolerance-related immune responses.

Limitations

Results should not be used in isolation or viewed as diagnostic. Interpretation requires context and careful correlation with symptoms and elimination trials.
Limited clinical consensus

Major allergy societies do not endorse IgG4 tests as standalone diagnostics. Use only in functional or exploratory settings.

Risk of over-restriction

Without guidance, users may remove many foods unnecessarily, leading to nutritional imbalances or food fear.

Frequency

Suggested cadence

Consider testing once if chronic symptoms persist without clear explanation and after basic interventions have failed. Retesting may be useful after 6–12 months if dietary changes are implemented.

Cost

Typical costs

Prices vary by panel size (e.g., 44, 90, or 270 foods) and provider. Typically ranges from $150–$350 USD.

Availability

Where available

Offered through many functional or integrative clinics and private labs, especially in Europe and North America. Not commonly available in standard hospital settings.

Preparation

How to prepare

No fasting is required. Avoid testing during acute illness or high-dose immunosuppressive therapy. Inform lab of any immunoglobulin therapies.

Interpretation

Results must be interpreted in the context of symptoms and used to inform (not dictate) short-term elimination protocols.
High reactivity (Red zone)

Foods in this range may warrant temporary elimination for 6–8 weeks, followed by structured reintroduction.

Low reactivity

Generally well tolerated unless strong symptom correlation exists. No restriction typically needed.

Alternatives

Elimination diet with symptom tracking

Often considered the gold standard — involves removing common triggers and reintroducing them one by one.

IgE allergy testing

Measures immediate allergic reactions but does not assess delayed sensitivities.

FAQ

Is IgG4 testing scientifically validated?

While not endorsed by major allergy organizations, some functional practitioners find value in IgG4 as a tool within a broader clinical picture.

Can I reintroduce foods after elimination?

Yes. After a 6–8 week elimination, reintroduce one food at a time while monitoring symptoms to assess individual tolerance.