TOPLINE:

Specific immunoglobulin E (IgE) testing of more than 23 million samples revealed that rates of sensitization to tree pollen varied significantly by tree species; male patients and urban residents had higher positivity rates. Increased sensitization was associated with adolescent age (10-19 years), atopic dermatitis, and asthma.

METHODOLOGY:

• Researchers sought to assess how often patients tested positive for allergen-specific IgE across demographic and patient groups and to map how sensitization varied by geographic region.
• They analyzed 23,932,544 specific IgE test results for pollen of 31 tree species from 3,067,173 patients, collected from a nationwide clinical laboratory between 2014 and 2023.
• They defined positive sensitization as having a specific IgE concentration of 0.10 or more kilounits of allergen-specific IgE per liter (kUa/L) and compared results to the historical threshold of 0.35 kUa/L.

TAKEAWAY:

• Overall, 38.7% of patients were sensitized to at least one tree pollen; species positivity rate ranged from 6.9% (queen palm) to 31.3% (olive).
• Men vs women had higher specific IgE positivity rate for tree pollen (29.7% vs 19.4%) across ages and species, peaking at 10-19 years.
• Rates of sensitization to tree pollen in allergic vs nonallergic patients were 1.57 times higher with atopic dermatitis, 1.24 times with asthma, and 1.13 times higher with rhinitis.
• Urban vs rural residents had higher mean positivity rates (21.4% vs 17.8%); ordering of tree allergens from most to least frequently positive at 0.10 kUa/L and 0.35 kUa/L thresholds matched closely, with spruce the main outlier.

IN PRACTICE:

“As ecoregions represent geographic areas with consistent environmental characteristics and relatively homogeneous flora, and most ecoregions span multiple states, it may add clinical value for laboratories to consider the creation of allergy test profiles for ecoregions instead of by state lines or some other arbitrary boundaries,” the authors wrote.

SOURCE:

Matthew Robinson, MS, Labcorp, Burlington, North Carolina, was the corresponding author of the study, which was published online on January 14, 2026, in The Journal of Allergy and Clinical Immunology.

LIMITATIONS:

It remained unclear whether findings reflected true population sensitization rates or physician ordering practices. The study lacked comprehensive data on pollen, used provider‑assigned International Classification of Diseases codes without validation or details on severity, and had a retrospective, uncontrolled design. Relatively low test volumes for some tree species and geographic regions may have limited generalizability.

DISCLOSURES:

This study was funded by Labcorp. Four authors reported being employees of the funding company. One author reported receiving grants, nonfinancial support, and personal fees from various companies including Phadia, Revenio, and the funding company.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.