A computer assisted coding system (CACS) is software that analyzes healthcare documents and produces appropriate medical codes for specific phrases and terms within the document.
Similar conceptually to "spell check," the software uses natural language processing in order to highlight key terms and phrases for ICD-9 CM, ICD-10 CM and the American Medical Association's Current Procedural Terminology coding. In addition, CACSs analyze the context to determine whether a particular instance requires coding. For example, the software can determine that the term "cancer" requires coding when it's a diagnosis, but not when it is referring to a "family history of cancer."
Traditionally such coding is performed by people called coders, but the shift toward technology-driven healthcare has increased the necessity and demand for medical coding systems -- especially with the growth in electronic health record implementation and the transition to ICD-10-CM. This has led to a hybrid system, in which CACS perform a majority of the medical coding, especially on routine procedures, and coders address more complex scenarios while auditing the CACS output.
According to the American Health Information Management Association (AHIMA), a CACS offers several advantages over manual coding, including increased productivity and efficiency in coding and the consistent application of coding rules. However, the cost of the computer assisted coding software and the increased chance for errors are potentially detrimental. An AHIMA study found that coders that used a CACS spent 22% less time coding a record than coders that didn't consult a CACS. The study also showed that a CACS that was unchecked by a coder was less accurate than a combination of the medical coding software and a manual coder.