Effect of food sample shelf life on prick-to-prick test reproducibility

Trophallergen Prick Tests (PT) : Influence of Food Sample Shelf Life on the Reproducibility of PT Results

We will test whether prick-to-prick skin tests with fresh versus stored (frozen or dried) native foods give the same results in adults with confirmed food allergies.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 100 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Centre Hospitalier Régional d'Orléans (Academic / other)
• Locations: 1 site (Orléans)
• Trial ID: NCT06872996 on ClinicalTrials.gov

What this trial studies

This single-center interventional study compares prick-to-prick skin test results obtained at the same visit using fresh native foods versus the same foods stored for varying periods (frozen or dried) in adults with known IgE-mediated food allergies. Each participant serves as their own control and may have several foods tested in a single roughly 30-minute session to avoid intra-individual variability. The main outcomes are concordance and reproducibility of wheal responses between fresh and stored samples, with 30 minutes of post-test observation by allergology nurses. Participants meet inclusion criteria including age ≥18 and prior diagnosis of grade 2–3 food allergy with evidence of sensitization; those with recent severe reactions or interfering medications are excluded.

Who should consider this trial

Good fit: Adults (≥18 years) with a prior allergologist diagnosis of IgE-mediated food allergy (Ring and Messmer grade 2–3) and evidence of sensitization who can attend a single in-person visit are ideal candidates.

Not a fit: People with recent severe anaphylaxis, recent asthma hospitalization, current systemic antihistamine or beta-blocker use, or who are under legal guardianship are excluded and would not receive benefit from this protocol.

Why it matters

Potential benefit: If successful, clinicians could reliably use stored food samples for prick testing, improving access and consistency in diagnosing food allergies.

How similar studies have performed: Prick-to-prick testing with fresh foods is an established method and some prior work indicates frozen or processed samples can retain allergenicity for certain foods, but reproducible results across many foods and storage conditions are not fully established.

Eligibility criteria

Inclusion Criteria:

1. Aged 18 and over.
2. Having a diagnosis of food allergy(ies) due to one or more of the food allergen studied, previously made by an allergologist, of grade 2 to 3 according to the Ring and Messmer classification.
3. Having given consent to participate in the study.

The diagnosis is made by the allergologist of the department due to the presence of a compatible clinical history implicating the tested allergen, the presence of evidence of sensitization to the allergen (positive prick-test and/or positive specific IgE assays), or even a positive oral allergen reintroduction test.

Exclusion Criteria:

1. Anaphylactic reaction dating less than 6 weeks
2. Hospitalization for asthma in the past 3 months
3. History of grade 4 anaphylactic reaction according to the Ring and Messmer classification.
4. Systemic antihistamine treatment in the 7 days preceding the test
5. Systemic beta-blocker treatment on the day of the test.
6. Protected person (under guardianship or curatorship)
7. Person under judicial supervision
8. Persons deprived of liberty
9. Person not affiliated with a social security insurance
10. Pregnant or breastfeeding women

Where this trial is running

Orléans

• Centre Hospitalier Universitaire d'Orléans — Orléans, France (Recruiting)

Study contacts

• Study coordinator: Minaxi Dr PATEL, PhD

Conditions Food Allergy; Prick test; Skin test; Trophallergen; Food sample; Fresh; Frozen; Fruit