BACKGROUND: Nurses register data in electronic health records, which can use various terminology and coding systems. The net result is that information cannot be exchanged and reused properly, for example when a patient is transferred from one care setting to another. A nursing subset of patient problems was therefore developed in the Netherlands, based on comparable and exchangeable terms that are used throughout the healthcare sector and elsewhere (semantic interoperability). The purpose of the current research is to develop a mapping between the subset of patient problems and three classifications in order to improve the exchangeability of data. Those classifications are the Omaha System, NANDA International, and ICF (the International Classification of Functioning, Disability and Health). METHOD: Descriptive research using a unidirectional mapping strategy. RESULTS: Some 30%-39% of the 119 SNOMED CT patient problems can be mapped one-to-one from the subset onto each separate classification. Between 6% and 8% have been mapped partially to a related term. This is considered to be a one-to-one mapping, although the meanings do not correspond fully. Additionally, 23%-51% of the patient problems could be mapped n-to-one, i.e. more specifically than the classification. Some loss of information will always occur in such exchanges. Between 1% and 4% of the patient problems from the subset are defined less specifically than the problems within the individual classifications. Finally, it turns out that 9%-32% of the terms from the subset of patient problems could not be mapped onto a classification, either because they did not occur in the classification or because they could not be mapped at a higher level. CONCLUSION: To promote the exchange of data, the subset of patient problems has been mapped onto three classifications. Loss of information occurs in most cases when the patient problems are transformed from the subset into a classification. This arises because the classifications are different in structure and in ...