Billing / Fees / Insurance

Insurance Billing: What's the Difference Between ICD-9 and CPT?

Kevin McNamee

A common question for practitioners beginning to bill insurance is, "What's the difference between CPT and ICD-9?" CPT stands for Current Procedural Terminology, whereas ICD-9 stands for International Classification of Diseases, volume 9.

The ICD-9 assigns a specific code to the diagnosis of the condition or disease being treated. This is a uniform method so that the third party, doctor and patients can understand what is being treated in the patient encounter. The ICD-9 comes in three volumes. Volumes one and two are the same, except volume one is organized alphabetically, while volume two is organized by systems. Volume three deals with surgical codes and is not relevant to doctors of Oriental medicine. Most editions contain volumes one and two combined. Volume three is usually sold separately. Your office will only need to replace the ICD-9 codebook every 10 to 15 years since these codes change infrequently.

Conversely, the CPT book is a listing of descriptive terms and identifying codes for reporting medical services and procedures performed by doctors. The purpose of the terminology is to provide a uniform language that will accurately describe treatment and diagnostic services, thus providing a uniform method of communicating between doctors, insurance companies and patients. The CPT codebook should be updated every 3-5 years.

In a concise statement, ICD-9 is the code used to describe the condition or disease being treated, also known as the diagnosis. CPT is the code used to describe the treatment and diagnostic services provided for that diagnosis. Anyone who bills a health insurance company should have a CPT and ICD-9 codebook in their office.

To obtain additional information about insurance billing codes, visit the website below and click on the "Your Practice" link.

October 2001
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