t becomes very difficult for pooling and combining of patients' laboratory test results from different healthcare providers for integrated care when using different set of the codes. LOINCreg (logical observation identifier names and codes) has been developed to facilitate the transmission and storing of clinical laboratory results among different sources of clinical laboratories since 1994. Currently, the LOINC codes are most comprehensive for the identifiers of laboratory tests, and widely adopted internationals. Since National Health Insurance (NHI) codes have been used nationwide in Taiwan, most clinical laboratories and hospitals have a mapping database between their internal codes and the NHI codes. In this paper, we present methods to create a NHI-LOINC mapping database as an intermediate medium, and develop a Web-based NHI-LOINC mapping system to facilitate the mapping from hospital internal codes to the LOINC codes. Our approach can reduce the learning curve and required domain knowledge for the LOINC due to familiarity of NHI codes. Hence, it can facilitate the adoption of LOINC codes in Taiwan