Coding mechanisms for diagnosis timing in the International Classification of Diseases, Version 11

BACKGROUND: Diagnoses that arise after admission are of interest because they can represent complications of health care, acute conditions arising de novo, or acute decompensation of a chronic comorbidity occurring during the hospital stay. Three countries in the world have adopted diagnosis timing codes for a number of years. Their experience demonstrates the feasibility and utility of associating an International Classification of Diseases, Version 9 or International Classification of Diseases, Version 10 diagnostic code with information on diagnosis timing, either as part of a diagnostic field or as a separate field. However, diagnosis timing is not an integrated feature of these two classifications as it will be for International Classification of Diseases, Version 11. METHODS: We examine the different types of diagnosis timing that can be used to describe complex patients and present examples of how the new International Classification of Diseases, Version 11 codes may be used. RESULTS: Extension codes are one of the important new features of International Classification of Diseases, Version 11 and allow more specificity in diagnosis timing. CONCLUSION: Imbedded and standardized diagnosis timing information is possible within the International Classification of Diseases, Version 11 classification system.