Methods and apparatus to correlate healthcare information are disclosed. An example method includes receiving a healthcare message from a first entity of a healthcare enterprise, wherein the healthcare message is configured according to a first identification schema of the first entity; identifying one or more subjects of the healthcare message for correlation into an electronic clinical information system; selecting one of a plurality of correlators for each identified subject to correlate each identified subject, wherein each of the correlators are customizable to handle a specific type of healthcare message subject; and correlating the identified subjects of the message to associate each of the identified subjects with an identifier internal to the electronic clinical information system.