Methods and apparatus to correlate healthcare information are disclosed. An example method includes receiving (400) a healthcare message from a first entity(104) of a healthcare enterprise(102), wherein the healthcare message is configured according to a first identification schema of the first entity(104); identifying(402) one or more subjects of the healthcare message for correlation into an electronic clinical information system(124); selecting(406) one of a plurality of correlators(224) for each identified subject to correlate each identified subject, wherein each of the correlators(224) are customizable to handle a specific type of healthcare message subject; and correlating(408) the identified subjects of the message to associate each of the identified subjects with an identifier internal to the electronic clinical information system(124).