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Preparing for ICD-10: Part 1

How ICD-10 Coding System Will Work

The healthcare industry is set to undergo an important change on October 1, 2015, when the mandatory adoption of the ICD-10 codes go into effect. The new code set, which increases the number of medical reporting codes from fewer than 14,000 to nearly 70,000, will greatly increase the industry’s ability to more specifically report diagnoses and medical procedures. However, the code set’s increased complexity, along with the requirement for more detailed physician documentation, presents a challenge for many healthcare providers.

ICD-10 requires an effective software system that allows providers to navigate the new and more expansive code set with ease. It is important that providers assess whether their current EMR is capable of supporting the transition or if they need to select a more qualified EMR vendor.

Today, we launch a three-part blog series dedicated to examining the challenges associated with the upcoming mandatory adoption of ICD-10 medical coding changes. The blog series, based on the white paper, “Preparing for ICD-10: What Your Practice Needs to Know,” closely explores changes medical practices will likely face as a result of this important coding transition and outlines the importance of providers using a qualified EMR that is capable of supporting this changeover.


On October 1, 2015, healthcare providers will experience a significant change in medical diagnosis and procedure coding with the mandatory implementation of the ICD-10 system. ICD-10 stands for International Classification of Diseases and Related Health Problems, 10th Edition. It is the most recent version of a medical diagnostic coding system that codes for diseases, signs and symptoms, complaints, abnormal findings, social circumstances and external causes of diseases or injuries. ICD-10 was first implemented in 1993 by the World Health Organization (WHO) to replace the previous version, ICD-9, which was developed in the 1970s.

The new coding system is set to replace ICD-9 this year. Currently, ICD-10 is being used for diagnosis coding in nearly every country except the United States. Switching from ICD-9 to ICD-10 is not optional, as the transition is required for all medical practitioners that are covered by the Health Insurance Portability Accountability Act (HIPAA). All practitioners covered by HIPAA must comply with the act’s provisions that require medical providers to adopt national standards for electronic healthcare transactions. 

The term “ICD-10” more specifically refers to ICD-10-CM, the diagnostic coding system’s clinical modification. Another designation, ICD-10-PCS, refers to the procedural coding system developed to report inpatient hospital procedures, and will be used by hospitals and payers. While the basic term “ICD-10” is exclusive to the diagnostic coding system, mentions of the upcoming ICD-10 changeover typically reference the concept of change in both systems.


The switch from ICD-9-CM to ICD-10-CM has been prompted by several factors. Most significantly, the current system, which is more than 30 years old, no longer has room for new diagnoses. Currently, each diagnosis is assigned a three-digit category, and each category may contain up to 10 subcategories. Most of these subcategories have already been assigned, and with new medical discoveries happening at a rapid pace, it leaves no room for new diagnoses in the database. 

ICD-10-CM will increase the number of available diagnostic codes more than fivefold, from about 13,600 three- to five-digit numeric codes to 69,000 three- to seven-digit alphanumeric codes. Much of this code increase is due to lateral growth — a code in ICD-9-CM may simply identify a condition of a body part (an ovary, for example), while ICD-10-CM allows for much more specific identification (right ovary, left ovary, unspecified ovary, etc.). This will allow for improved analysis of disease patterns and treatment outcomes, and will also help to streamline claims submissions, as simplified codes make it easier for patients to understand their claims. 

Adopting ICD-10 is also critical when it comes to ensuring that the U.S. medical system is compatible with the rest of the world, allowing for better clarity in the communication between different nations when describing diseases, morbidity and mortality. 

In many important ways, ICD-10-CM will function similarly to ICD-9-CM. The codes will be organized in a similar way, and all guidelines, rules and conventions will see few changes. However, providers will also notice that significant coding improvements have been made. For example, a single code will now be able to report both a disease and its current manifestation; rather than simply reporting “fracture,” the new system will include codes that differentiate between initial fractures, follow-up visits with the fracture in malunion/nonunion and more. This eliminates the need to combine several different medical codes, as is the case under ICD-9-CM, which can often lead to confusion.