A system for centrally managing a set of network-connected laboratory instruments is disclosed. For example, the system includes a centralized database that includes information about the instruments in the system and about the authorized users of the system. In particular, the centralized database indicates which users are authorized to use each of the instruments in the system. The database may also include information about the operations that each user is authorized to perform using the instruments and information indicating whether tests performed by each instrument must be signed using one or more electronic signatures. The system may recognize a number of "roles," each of which is associated with a particular set of rights, and may assign one or more roles to each user. Instruments and other elements of the system may access the centralized database over a network to enforce the user rights represented by the information in the database.