There is an international need to share health data across countries through ecosystems such as the European Health Data Space to improve access and promote both primary and secondary use of health data. The aim of this study was to explore the implications of coding nursing interventions with multiple classification systems on nursing documentation. Electronic health records originally captured via the Finnish Care Classification System (FinCC) were coded with the LEP Nursing 3 intervention classification to gain an understanding of the implications of applying different nursing classification systems. A total of 2807 annotations were made to 2594 nursing data entries, most of which (85.6%) were related to monitoring. There were inconsistencies in the documented entries on the FinCC component level and structured headings and subcategories were seldom used. Also, single entries often included multiple interventions under the same heading. In conclusion, implementation of health data exchange platforms using different health data standards poses challenges. Even if the standards are harmonised, their clinical use may deviate from the intended design. Coding LEP Nursing interventions in Finnish electronical health records related to movement, treatment, and safety might be feasible based on data documented via FinCC. Further research is recommended to determine the applicability of LEP to Finnish health records across all areas of nursing care.