A Detailed Look at Describing Diagnoses Using the International Classification of Diseases

A Detailed Look at Describing Diagnoses Using the International Classification of Diseases

Norman A. Cohen MD

Describing medical services for billing purposes involves selecting a procedure code and a supporting diagnosis code. The International Classification of Diseases (ICD) is far and away the most prevalent system for reporting diagnoses and the American Medical Association (AMA) Current Procedural Terminology (CPT) (Current Procedural Terminology © 2006 American Medical Association.® All Rights Reserved. Applies to all CPT code references in this chapter) publication is the primary way to report the services of physicians and many allied health professionals. In some situations, physicians may need to use Medicare’s Health Care Procedural Coding System (HCPCS) when reporting procedural services. In addition, hospitals use a section of the ICD to report inpatient procedural services. In the next few years, hospitals will transition to a new edition of ICD, many years in the making, known as ICD-10.


In the United States, the system for reporting medical diagnoses is the International Classification of Diseases Ninth Revision—Clinical Modification, or ICD-9-CM. The World Health Organization (WHO) developed the ICD system. The National Center for Health Statistics (NCHS) and the Centers for Medicare and Medicaid Services (CMS) maintain the ICD-9-CM, which has been modified from the WHO’s ICD-9 to address specific requirements of the U.S. health system. ICD-9-CM is “the official system of assigning codes to diagnosis and procedures in the United States.” Agencies that categorize mortality data from death certificates use the unmodified ICD-9 system. The WHO first published ICD-9 in 1979, and the U.S. government published ICD-9-CM at about the same time. As we will discuss when considering procedural coding, the diagnosis and procedural coding systems will see major changes when the next version of ICD, the tenth revision, becomes the standard in just a few years.

ICD-9-CM has three volumes. Volume 1 lists all disease code numbers and descriptors in the form of a very long table. Volume 2 has an alphabetical index to the disease entries. And Volume 3 contains an alphabetical index and
a tabular list of the procedural coding system used by hospitals for describing surgical, diagnostic, and therapeutic interventions. In this section, we will discuss the codes found in Volumes 1 and 2, and address Volume 3 in the chapter on procedural coding.

The ICD-9-CM divides diseases into 17 broad categories. Examples include “diseases of the nervous system and sense organs,” “diseases of the digestive system,” and “congenital anomalies.” In addition, a supplementary classification system, known colloquially as “V-codes,” describes situations when conditions other than current disease or injury are applicable. One would report a past history of a now-inactive condition or a family history of a disease state with a V-code rather than a primary diagnosis code. For example, a family history of a malignant neoplasm in the gastrointestinal tract (V16.0) could support a screening colonoscopy at a younger age than is currently recommended for the general population. Think V-codes for risk factors and diagnosis codes for known patient conditions.

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Jul 1, 2016 | Posted by in ANESTHESIA | Comments Off on A Detailed Look at Describing Diagnoses Using the International Classification of Diseases

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