For more than 20 years, the NLM has maintained on-line databases containing information about hazardous substances and toxic releases into the environment, as well as bibliographic information related to infectious diseases, new disease vectors, community prevention strategies, and the organization of public health services. Today, more than 100,000 institutions and individuals search these databases on line, many using Grateful Med, a user-friendly microcomputer search package. The NLM directs the National Network of Libraries of Medicine (NN/LM) whose more than 4,000 members work to equalize access to information for health professionals, irrespective of their geographic location. Although NLM databases are readily available at low cost through the Internet and commercial telecommunications networks and NN/LM document delivery and training services are available throughout the country, many public health workers do not know how to access them.
Since 1986, the NLM has also directed the Unified Medical Language System (UMLS) project. The goal of this project is to promote timely access to up-to-date health information by improving the ability of computer programs to "understand" the actual meaning of user inquiries and to use this understanding to retrieve and integrate relevant information from many disparate machine-readable information sources (6). The main UMLS database now contains terms for 223,000 health-related concepts from more than 30 source vocabularies. Since it preserves the link between the concepts and terms in the original vocabularies, this Metathesaurus can be used to translate between a user's terminology and the different vocabularies used in different databases. While originally conceived as an information retrieval tool, the UMLS also provides a vehicle for disseminating a detailed and uniform vocabulary for computerized medical records systems. It might also evolve into a standard, multipurpose nomenclature for logically integrated health information systems -- one that could capitalize on information being recorded in computerized medical records and be mapped to multiple classifications, such as ICD-10 for international morbidity and mortality reporting and CPT for physician billing. Work is currently underway to expand the UMLS to include unique public health concepts and to test the "health vocabulary" in both clinical and public health settings.