ICD-10: An Illustrated Classification of Diseases

Topics: Costs and Prices, Medical Bills and Debt, Health Information Technology, Electronic Health Records, Federal Government, Health Care Legislation, Providers

One month ago, the U.S. health care system transitioned from the 9th to the 10th edition of the International Classification of Diseases, or in the jargon embraced by the medical community: from ICD-9 to ICD-10. Despite years of delay and concerns from the industry, many have reported the transition to be relatively smooth.

ICD-10 features three-character or seven-character medical codes, which were developed by the World Health Organization and have been used by member states since 1994. The codes are used to diagnose individuals, as well as to track trends in population health, mortality and morbidity and create research databases.

Perhaps most importantly, in the U.S., ICD is used to determine medical billing and reimbursement.

In the Journal of AHIMA, Rich Averill debunked some of the misunderstandings about ICD-10. Health care professionals often cite the costs associated with the transition. According to a RAND Corporation cost-benefit analysis -- commissioned by an HHS advisory committee -- adopting ICD-10 codes should lead to more accurate payments, fewer rejected or fraudulent insurance claims, improved disease management, and clearer understanding of new treatments.

Across All Disciplines

No one is expected to use -- or know -- every ICD-10 code, because they are meant to cover every field of medicine. According to Vox, While ICD-9 had 14,000 codes, ICD-10 has 68,000 codes, which include more ailments and injuries but also specifies on what side of the body an injury happened. CMS breaks down what every alphanumeric character of an ICD-10 code means, and how to translate them into something readable.

For instance, 724 codes begin with F and represent "mental, behavioral and neurodevelopmental disorders," which would be essential for a psychiatrist and all but useless to a podiatrist. That category includes everything from F43.11, "post-traumatic stress disorder, acute," to F55.1, "abuse of herbal or folk remedies."

Codes beginning with R are a sort of catch-all: "symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified." That includes codes like R46.1, "bizarre personal appearance," or R46.0, "very low level of personal hygiene."

By far the largest category is "injury, poisoning and certain other consequences of external causes," which contains 39,869 codes, all beginning with S or T.

Second Attack by a Duck? Not Quite

A common misconception of ICD-10 codes is related to a distinction in the seventh character -- A, for initial encounter; D, for subsequent encounter; or S, for sequela.

Ann Zeisset, an independent consultant on ICD-10, explained in the Journal of AHIMA that a subsequent encounter does not mean a patient had the same injury twice, but rather that a patient had a subsequent encounter with a provider -- it clarifies the stage of treatment. The intent behind this aspect of ICD-10 coding is to classify the kind of care that happens during healing or recovery.

Meanwhile, "sequela" is a term for complications or conditions that came about as a direct result of an injury -- for example, a scar that forms after a burn.



Thirty Years in the Making

The National Center for Health Statistics adapted ICD to fit the unique needs of the U.S. health care system. Maxim Topaz writes in a history of the ICD-9 to ICD-10 transition published in the journal Perspectives of Health Information Management that NCHS's clinical modification of ICD-10 -- or ICD-10-CM -- wasn't first released for public comment until 1998. Numerous debates about the effects on cost, revenue and clinical outcomes perpetually postponed implementation until this year.

Ed Hock, director of revenue cycle solutions at the Advisory Board Company, said one of the big hurdles health care providers in the U.S. needed a lot of time to overcome was the technological transition from ICD-9 to ICD-10. The switch from a five-digit numeric system to a seven-digit alphanumeric system required thorough IT testing that Hock likened to Y2K. (The Advisory Board is the publisher of American Health Line.)

What About ICD-11?

The U.S. is a bit behind on ICD implementation: ICD-11 is scheduled for release in 2018, WHO says. While some experts had proposed leapfrogging ICD-10 and going straight to ICD-11, a 2012 HHS rule on ICD-10 implementation explained after performing a cost-benefit analysis, it became clear that implementing ICD-10 was the best option. Other stakeholders -- including the American Medical Association and the Medical Group Management Association -- disagreed.

In an interview with Healthcare Finance, Hock noted, "To say go straight to ICD-11 is mostly saying we shouldn't do anything for a long time." He added, "A push to go to ICD-11 is really a push to not change at all for at least another five to seven years, and most likely longer than that."

-- text and art by Rob Reeve, staff writer