About HL7

HL7 is a standard for exchanging information between medical applications and is an abbreviation of Health Level Seven. Level Seven refers to the seventh OSI layer protocol for the health environment. HL7 defines the format and the content of the messages that applications must use when exchanging data with each other under various circumstances.

Hospitals and other medical institutions typically use many different types of systems to communicate with one another. Everything, from patient records to billing information, is tracked and recorded in computer systems. In order for these different types of systems to communicate with each other, they use a standard like HL7.

In the computer world, a protocol is a formal, well-defined standard for exchanging information between computer applications.

An important part of the HL7 standard is the ACKnowledgment protocol, also known as an ACK. Every time an application accepts a message and consumes the data, it is expected to send an ACKnowledgment message back to the sending application. The sending application is expected to keep on sending a message until it has received an ACK message.