The Arden syntax is a grammar for describing medical conditions and recommendations, used in Medical algorithms.
Medical logic modules are written in Arden syntax, and are called by a program - an event monitor - when the condition they are written to help with occurs. Arden syntax was formerly a standard under ASTM, and is now part of HL7.
It derives from work at the Regenstrief Institute, Inc., an international non-profit medical research organization with one of the world's largest brain trusts of physician Medical Informaticians as well as Health Services Researchers. The CARE system developed at Regenstrief, delivers reminders or hints to clinicians regarding patient treatment recommendations (e.g. the next clinic appointment, based on rules applied to the digitized notes and pertinent patient data stored in the system. Additionally, LDS hospital in Salt Lake City (HELP System...) has contributed much to this standard as well as body of knowledge. Arden syntax dates from 1989.