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Key Terms


Disease codes

Impairment codes

Disability codes

Operational definitions

Chapter Outcomes

  • Describe the benefits of using coding systems for patient documentation.

  • Describe the qualities of useful coding systems.

  • Identify examples of coding systems used in rehabilitation settings.

A coding system is a set of symbols and their definitions used to categorize or organize information about a group of things or people. Code definitions may reflect relative values, such as the coding of levels of strength, or they may be based on mutually exclusive conditions, such as the coding of blood types. Coding systems allow clinicians to read about, document, and compare patient or intervention characteristics using a common language. This chapter will describe the benefits of integrating coding systems into documentation, describe the qualities of useful coding systems, and provide examples of some coding strategies.


Medical coding has its origins in the middle 1700s for epidemiological tracking of causes of death (Coiera, 2003). There are many coding systems that describe patient characteristics, and their unique foci influence how patient outcomes are studied. Coding systems are the structural building blocks for data sets because they provide efficient methods of recording detailed clinical information. This section briefly describes the generic benefits and limitations associated with using coding systems in clinical documentation.

Standardization of Terminology

One important benefit of using coding systems is that terminology is standardized for all users. In an evolving profession such as physical therapy, multiple terms have been generated to describe clinical observations. For example, hyperreflexia, spasticity, hypertonicity, and excessive tone all describe a state of muscle reactivity in people with central nervous system injuries. Dizziness, vertigo, and lightheadedness are terms used to describe similar perceptions related to vestibular or circulatory impairments.

When multiple terms describe similar phenomena in patient documentation, it becomes difficult to determine whether clinicians are referring to similar or different processes or observations. A coding system links a specific definition to a term or to a set of synonyms, thus differentiating the terms that describe similar but not equivalent observations. Agreement on a single set of terms and definitions allows for standardization of language and of procedures and improves ease of communication. For example, before the Guide to Physical Therapist Practice (1995) was published, clinicians had used the terms examination and evaluation interchangeably. In the Guide, each term is distinguished by its own definition to reflect a different phase of patient care management. Publication and repeated use of the definitions have clarified communication for a wide range of audiences and consumers.

Reduction of Variability in Documentation

In rehabilitation settings, using a standardized coding system to describe patient conditions reduces variation in patient descriptions and provides common understandings ...

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