1. Information and instructions at the beginning of each of the six major sections of the Current Procedural Terminology (CPT) code book when coding medical services and procedures. Additional guidelines are provided at the beginning of each subsection and for code ranges. Guidelines present definitions and explanations of terms and phrases, applicable modifiers, explanation of notes, unlisted services, special reports information, and clinical examples. These are all factors to appropriately interpret and report the procedures and services contained in a particular section. 2. Written general rules and procedures to assist physicians in making a diagnosis and giving treatment. These are set down to change practice styles, lessen unnecessary care, and reduce costs. Depending on the region of the United States, may also be referred to as medical practice parameters, clinical practice guidelines , or clinical protocols .