Systematic review supports the idea that no alternative test presently replaces elimination diet test and oral food challenge to diagnose canine adverse food reactions.

BACKGROUND: Adverse food reactions in dogs are clinically heterogeneous and overlap with canine atopic dermatitis, and diagnosis still relies on an elimination diet test followed by oral food challenge (EDT+OFC). Numerous allergen-specific tests have been proposed, but their diagnostic value remains controversial. Our objective was to identify, synthesize, and critically evaluate the diagnostic tests used or investigated for canine food allergy, with emphasis on their clinical validity, applicability, and agreement with the EDT+OFC reference standard.

METHODS: In accordance with PRISMA (ie, Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines, Scopus and PubMed were searched without publication-year restrictions, and records were independently screened in duplicate at the title, abstract, and full-text stages.

RESULTS: A meta-analysis was not feasible owing to heterogeneity. Fifty-nine studies (1986 to 2025) from 16 countries were included and grouped into elimination/provocation diets and serological, cutaneous, cellular, and molecular tests. The most consistently validated approach remained EDT+OFC. Serological IgG/IgE (and salivary) tests were poorly correlated with clinical outcome; the standardized patch test showed the best cutaneous performance (high negative predictive value), cellular tests (lymphocyte proliferation) showed the closest concordance with the OFC, and molecular/proteomic methods advanced allergen characterization and the understanding of cross-reactivity.

CLINICAL RELEVANCE: No alternative test reliably replaces EDT+OFC. Although patch testing may seem beneficial, its practical value is limited, and cellular assays represent a promising area for future biomarker research; standardized protocols and well-designed prospective studies are needed.