What is ICD-10-CM?

ICD-10-CM is the International Classification of Diseases, 10th Revision Clinical Modification. This is a new/revised diagnosis classification system developed by the Centers for Disease Control and Prevention (CDC) for use in all United States health care settings. ICD-10-CM will replace the existing diagnosis code set, ICD-9-CM (International Classification of Diseases, 9th Edition, Clinical Modification, Volumes 1 and 2). 

You should be planning and taking action now to be compliant by Oct. 1, 2015.  


When is the ICD-10-CM compliance deadline?

The deadline is Oct. 1, 2015.

What does ICD-10-CM compliance mean?

ICD-10-CM compliance means that all HIPAA-covered entities must implement ICD-10-CM for use in standard electronic transactions (including but not limited to claims) for health care services provided on or after Oct. 1, 2015.

Will ICD-10-CM replace Current Procedural Terminology (CPT) coding?

No. The transition to ICD-10-CM does not affect CPT coding for physician services.


Who is affected by the transition to ICD-10? If I don’t deal with Medicare claims, will I have to transition?

Everyone covered by HIPAA must use ICD-10-CM starting Oct. 1, 2015. This includes health care providers and payers who do not deal with Medicare claims. Organizations that are not covered by HIPAA but use ICD-9-CM codes should be aware that their coding may become obsolete if they do not transition to ICD-10-CM.

What happens if I don’t switch to ICD-10-CM?

If you don’t transition to ICD-10-CM, all your claims for all health care services performed on or after Oct. 1, 2015 will not be processed, therefore risking claims denials. NOTE: Claims for services provided before Oct. 1, 2015, must use ICD-9-CM diagnosis codes.

Why is the switch to ICD-10-CM happening?

The health care industry is making the transition from ICD-9-CM to ICD-10-CM because:

  • ICD-9-CM codes provide limited data about patients' medical conditions. ICD-9-CM is 30 years old, it has outdated and obsolete terms, and is inconsistent with current medical practices. Also, the structure of ICD-9-CM limits the number of new codes that can be created.
  • ICD-10-CM codes allow for greater specificity and exactness in describing a patient’s diagnosis and in classifying inpatient procedures. ICD-10-CM will also accommodate newly developed diagnoses, innovations in technology and treatment, performance-based payment systems, and more accurate billing. ICD-10-CM coding will make the billing process more streamlined and efficient, and this will also allow for more precise methods of detecting fraud.

Codes change every year, so why is the transition to ICD-10-CM any different from the annual code changes?

ICD-10-CM codes are completely different from ICD-9-CM codes. Currently, ICD-9-CM codes are mostly numeric and have three to five digits. ICD-10-CM codes are alphanumeric and contain three  to seven characters. ICD-10-CM is more robust and descriptive with "one-to-many" matches to ICD-9-CM in some instances. Like ICD-9-CM codes are now, ICD-10-CM codes will be updated every year. ICD-9-CM codes will not continue to be updated after Oct. 1, 2015.

How does ICD-10-CM differ from ICD-9-CM for diagnosis coding?

ICD-10-CM is not just an update of ICD-9-CM codes. It is a restructuring of the diagnosis classification system with far more alpha numeric codes, expanded code lengths and narrative descriptions allowing for greater granularity. The following table illustrates the key differences:

Classification system

Number of codes




  • 3-5 digits
  • Digit 1 is alpha (E or V) or numeric
  • Digits 2-5 are numeric



  • 3-7 digits
  • Digit 1 is alpha
  • Digit 2 is numeric
  • Digits 3-7 are alpha or numeric

Will I need to use both ICD-9-CM and ICD-10-CM codes during the transition?

Practice management systems must be able to accommodate both ICD-9-CM and ICD-10-CM codes until all claims and other transactions for services before Oct. 1, 2015 have been processed and completed. Prompt processing for ICD-9-CM transactions as the transition date nears will help limit disruptions and will limit the time frame when dual code sets need to be used.

What steps should I take to prepare for a smooth transition to ICD-10-CM?

Implementation planning for ICD-10-CM should begin immediately if it's not already underway, regardless of the size or function of your practice. ICD-10-CM implementation is not just a billing or Information Systems project because the organizational effect of the transition will be broad and deep. For providers who have not yet started to transition to ICD-10-CM, this timeline provides you with some steps to take now. Some of these activities, such as establishing a transition team and communicating to internal staff, might not be necessary for small practices where one or two people will be handling the transition activities. Ensure an impact assessment is conducted as soon as possible to enable timely planning, development, education, testing, and implementation.

What do providers need to do to make sure their ICD-10-CM systems are working properly?

Dermatologists should plan to test their ICD-10-CM systems early to help ensure they will be ready by the compliance date. Plan to test claims, eligibility verification, quality reporting, and other transactions and processes that involve ICD-10-CM codes from beginning to end. It is important to test both within your organization and with your payers and other business partners.

Beginning steps in the testing phase include:

  • Working with practice management system and/or EHR vendors/IT staff and coders/billers to develop and test processes and systems using ICD-10-CM codes.
  • Determining when you will be ready to test, and working with payers and any clearinghouses or billing services that you use to schedule testing.
  • Developing a testing plan that outlines key dates and milestones for when tests should be completed.

If I transition early to ICD-10, will CMS be able to process my claims?

No. CMS and other payers will not be able to process claims using ICD-10-CM until the Oct. 1, 2015 compliance date. However, your organization will need to work with your internal team and with business trading partners to test your software systems from beginning to end. This involves testing claims, eligibility verification, quality reporting and other transactions and processes using ICD-10-CM to make sure the new code set can be processed correctly.

Where can I find the ICD-10-CM codes?

The ICD-10-CM code sets and the ICD-10-CM official guidelines are available free of charge on the "2013 ICD-10-CM and GEMs" pages of the CMS ICD-10 website.

Is there a one-to-one match between ICD-9-CM and ICD-10-CM?

No, there is no one-to-one match between ICD-9-CM and ICD-10-CM due to a variety of reasons:

  • There are new concepts in ICD-10-CM that are not present in ICD-9-CM.
  • For a small number of codes, there is no matching code in the General Equivalence Mappings (GEMs).
  • There may be multiple ICD-9-CM codes for a single ICD-10 code.
  • There may be multiple ICD-10 codes for a single ICD-9-CM code.

Where can I find crosswalks from ICD-9-CM to ICD-10-CM codes?

Centers for Medicare and Medicaid Services (CMS) and the Centers of Disease Control and Prevention (CDC) have developed General Equivalence Mappings (GEMs) to show generally equivalent relationships between ICD-9-CM and ICD-10-CM codes. However, the greater granularity and newness of ICD-10-CM compared to ICD-9-CM often result in one-to-many, one-to-none, and sometimes many-to-many mappings in addition to one-to-one mappings. The GEMs are not to be used as a coding source but rather as a coding resource to help you understand the granularity of ICD-10.

A more specific code crosswalk is available here.

Why should I prepare now for the ICD-10-CM transition?

The transition from ICD-9-CM to ICD-10-CM will change how you do business. Health care organizations, from large national plans to small provider offices, laboratories, medical testing centers, hospitals, and more will need to devote staff time and financial resources for transition activities. Activities include:

  • Identifying how ICD-10-CM will affect your organization.
  • Developing a plan for implementing ICD-10 and creating a timeline of activities.
  • Working with vendors on new software/systems to accommodate ICD-10.
  • Coordinating with vendors, payers, and other business partners about ICD-10, especially about testing transactions and processes that use ICD-10.

The transition will go much more smoothly for organizations that plan ahead and prepare now. The AAD website has resources to help you prepare.


What type of training will providers and staff need for the ICD-10-CM transition?

The experts recommend that training begin no more than six to nine months before the Oct. 1, 2015, compliance deadline. Training needs will vary for different organizations, but it is projected to take 16 hours for outpatient coders. Coders in physician practices will need to learn ICD-10-CM diagnosis coding only. Take into account that ICD-10-CM coding training may be integrated into the CEUs that certified coders must take to maintain their credentials. In addition, some high-level ICD-10-CM training will be required earlier so that staff can conduct testing in 2013. This includes training to learn the new ICD-10-CM systems and understand how the structure and granularity of the ICD-10-CM codes will affect clinical documentation.

aad_coding_today_100 AADCodingToday: a new subscription-based electronic coding software.
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ICD-10 crosswalk Link the most frequently used ICD-9-CM codes to corresponding ICD-10-CM codes.
dialogues_logo Dialogues in Dermatology: The Road to ICD-10 features Mark Kaufmann, MD, and Murad Alam, MD, co-chairs of the ICD-10 Workgroup, giving ICD-10-CM background information as well as tips for a successful, seamless ICD-10-CM transition.
ICD_10_ebook 2015 ICD-10-CM Coding for Dermatology eBook: Prepare for a successful transition to the new ICD-10-CM coding system with this easy-to-use ICD-10 coding resource, complete with official coding guidelines and reporting instructions.
For more information or for answers to specific coding and reimbursement questions, email AAD's Manager of Coding and Reimbursement Faith McNicholas, RHIT, CPC, CPCD, PCS, CDC, at fmcnicholas@aad.org.

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