Optimising Allergen Classification in ICD-11: An Insight into a Landmark Study

In the world of medicine, allergy diagnosis and management hinge heavily on the accurate identification of triggers or causative allergens. Despite their significance, allergens have not found representation in the International Classification of Diseases (ICD), the comprehensive health information coding system governed by the World Health Organization (WHO). The recently published study by Tanno et al. (2023) brings a refreshing change to this narrative. It presents a pioneering effort to incorporate allergens into the ICD, specifically, the 11th Revision (ICD-11). This blog post delves into the groundbreaking study and its implications for clinical coding in the healthcare sector.

An Unmet Need in Clinical Coding

The previous versions of the ICD have made no room for allergens, leaving a critical gap in the classification of diseases. This limitation has curtailed the scope of appropriate risk assessments, patient counselling, and personalised treatment plans. With the advent of the ICD-11, the opportunity to amend this discrepancy and enhance the precision of clinical coding has emerged.

The Path to Allergen Integration

Tanno et al. (2023) initiated their study with the Logical Observation Identifiers Names and Codes database, which houses 1444 allergens. Two independent experts engaged in the initial allergen selection process, adhering to specific technical criteria. Subsequently, a second selection round considered the ‘real-life’ relevance of allergens based on the frequency of their occurrence.

The result was a comprehensive shortlist of 1109 allergens, equating to 76.8% of the original list. The selected allergens included plants (36.4%), drugs (32.6%), animal proteins (21%), mould and other microorganisms (1.5%), occupational allergens (0.4%), and miscellaneous allergens (0.5%).

Implications for Clinical Coding

The introduction of allergens in ICD-11 as proposed by Tanno et al. (2023) marks a significant advancement in clinical coding. The current allergen list could act as a springboard for health providers and coders, enabling them to assign more accurate diagnostic codes for allergy-related conditions. This progress could enhance patient care quality by improving risk assessments, facilitating patient and caregiver counselling, and enabling the design of individualised treatment strategies.

The current study illuminates the potential of the ICD system to evolve and encompass complex and nuanced aspects of health conditions, like allergens in this instance. It sets a precedent for other unrepresented areas within the ICD, fostering a more comprehensive and precise clinical coding approach.

The Future of Clinical Coding

The inclusion of allergens in the ICD-11 is a tremendous leap forward in clinical coding. However, it’s just the beginning of an expansive journey. This pioneering work by Tanno et al. (2023) should inspire continued efforts to improve the specificity and accuracy of the ICD system, thereby enhancing disease identification and management strategies globally.

In the end, the goal is clear – a more inclusive, comprehensive, and robust ICD system that better serves healthcare providers and patients alike. Through meticulous research and consistent innovation, we can move steadily towards this objective, transforming the landscape of clinical coding in the process.


Tanno, L. K., Briand, Y., Mary, M., Khan, D. A., Sublett, J. L., Corbett, M. L., Pawankar, R., Del Giacco, S., Torres, M. J., Ansontegui, I. J., Ebisawa, M., Martin, B., & Demoly, P. (2023). Optimization of the allergen classification of the International Classification Of Diseases, 11th Revision (ICD-11). Journal of Allergy and Clinical Immunology, DOI: https://doi.org/10.1016/j.jaci.2023.03.019

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