Coding Corner: Cleaning up the code set—How to influence ICD-10-CM Index and Tabular List changes

CDI Journal - Volume 14, Issue 1

by Kay Piper, RHIA, CDIP, CCS
Exciting changes to ICD-10-CM are published in an often-overlooked document called the Addenda. It lists additions, revisions, and deletions to the Alphabetical Index and Tabular List. This might seem mundane until you realize the changes’ potential effect on coding and CDI. The National Center for Health Statistics (NCHS) is the federal agency responsible for maintaining the ICD-10-CM code set, and they want our suggestions for what to add, remove, or change. You can submit a suggestion simply by emailing them. Note that this article focuses on Addenda for ICD-10-CM codes; the Centers for Medicare and Medicaid Services (CMS) is the federal agency responsible for maintaining ICD-10-PCS, and code requests for ICD-10-PCS should go to CMS, not NCHS. To help you get started, take a look at Figure 1 on p. 33 for a list of links and email addresses.

NCHS’ process for addenda
NHCS provides a public process for changes to Alphabetic Index and Tabular List entries. These changes may be easy fixes such as correcting typos, or they may have code assignment implications, such as changing an Excludes1 note to an Excludes2 note.

Addenda and code proposals are posted online where they are accessible to the public at any time. This keeps the process transparent and helps coders and CDI professionals understand why changes occurred—even years later. ICD-9-CM code proposals are available back through 1998, and ICD-10-CM proposals are available back through 2010.

New codes and Addenda are proposed biannually at the ICD-10 Coordination and Maintenance Committee (C&M) meeting. The Addenda are usually presented at the end of the meeting day. The committee posts proposed Addenda in the C&M agenda prior to the meeting (see Figure 2 on p. 33; p. 63 of the C&M agenda has proposed Tabular changes, and p. 77 has proposed Index changes). Files are downloadable, allowing the public to review and prepare comments. Comments must be submitted in writing during the stated comment period, which typically lasts several weeks following the meeting. NCHS and CMS consider all the comments before making a final decision. Input from any one commenter may lead to a modification in the committee’s proposals.

Addenda’s effects
It’s important to review the Addenda because they may affect coding for health data studies, payment, and/or reporting codes that are CC/MCCs. The Addenda may also affect the All Patient Refined Diagnosis Related Group (APR-DRG) severity of illness (SOI)/risk of mortality (ROM) scores. For instance, the fiscal year (FY) 2021 Addenda (presented at the September 2019 C&M meeting) proposes that the Excludes1 note prohibiting R57.0, Cardiogenic shock, be changed to an Excludes2. This would allow it to be reported with I46.-, Cardiac arrest. Both are MCCs, but the addition of cardiogenic shock would increase the SOI from 2-moderate to 3-major for the APR-DRG. See Figures 3 on p. 33 and 4a.–4b on p. 34.

Addenda may have query implications as well. For instance, currently ICD-10-CM has no unique code for critical limb ischemia, an advanced stage of peripheral vascular disease (PVD) causing severe pain, non-healing wounds, and gangrene. Rather than assigning the nondescript code for ischemia (I99.8, Other disorders of circulatory system; the code it defaults to), which groups to MS-DRG 303, Atherosclerosis without MCC, CDI staff may consider querying for I73.9, PVD, which groups to MS-DRG 301, Peripheral Vascular Disorders without MCC. The proposed Addenda for codes effective on October 1, 2020, have both Index and Tabular entries directing to I70.-, Arteriosclerosis (also MS-DRG 301), thus eliminating the need to query.

Types of corrections
Suggestions range from updating clinical terminology to considering the effect of new coding guidelines to ensuring correct spelling. Many who submit suggestions are clinical/technical editors working on updating code books for publishers. Often, ideas for suggestions come from coding dilemma discussions posted on professional community message boards. See the sample email in Figure 5 on p. 35 that suggests addition of Excludes1 notes as well as an inclusion term. Note that the reference for the change is provided in the email (it’s based on C&M meeting minutes). Also, note that the suggested entries appear exactly as they would in the Tabular List in terms of headers and spacing. All the actions to “add” appear in the left margin, which is the correct way to show how the entry would look in the actual code book.

What not to submit
CDI professionals strive to ensure their work helps their organizations receive appropriate payment and accurately report quality of care data. While these are important goals, ICD-10-CM’s primary purpose is tracking morbidity. When requesting a new code or a code change, do not include information regarding a code’s effect on reimbursement or quality measures. These code determinations fall outside the purview of the NCHS/C&M committee and will weaken the proposal. Also, do not ask NCHS to answer coding questions; submit those to the American Hospital Association’s (AHA) Coding Clinic. However, you may forward Coding Clinic answers to NCHS if they would help the committee consider frequently used codes for which Alphabetic Index or Tabular List changes would provide widespread benefit.

Process for submitting
Stay organized using the following suggestions:

  • Keep a running list of suggestions as well as whether and when they were implemented.
  • Create a folder to store your documentation on issues to send in, and another one for suggestions that have been implemented.
  • Save emails from coworkers or other sources who offer ideas for suggestions.
  • Submit suggestions by batch rather than individually, if applicable. Each submission can contain multiple suggestions.
  • Send screen captures to visually illustrate the issue. Use the official NCHS files rather than an online codebook or an encoder, which could vary in look from the official version.
  • Type suggestions as they would be displayed in the Alphabetic Index or Tabular List. This helps everyone visualize the changes.
  • Copy/paste proposed Addenda into a Word® document, then format them according to how you’d like to see the final entries. There is no template or format required for your comments, although the suggested entries must be written to look exactly like the code book entry. Use prior Addenda as a guide and refer to Figure 6 on p. 35.

Support your submission by doing the following:

  • Give the facts. State, for example, “The Index says this, but that sends you to a different diagnosis.”
  • Resist saying something is an error. It might not be.
  • Include background information so everyone understands the changes being suggested.
  • Cite Coding Clinic advice if applicable.
  • Explain how the entry was categorized in ICD-9-CM and how it’s different in ICD-10-CM. Should it be the same? Did it inadvertently get changed?
  • Review entries in the World Health Organization’s (WHO) version of ICD-10, which NCHS modifies for usage in the United States. NCHS tries not  to change the coded data too much to ensure that it matches WHO’s data (see Figure 1 for references).
  • Have a coworker review your suggestion when possible. Sometimes another person can catch something that should be changed.
  • Research the Alphabetic Index and Tabular List to see if there are other entries in which to place your suggestion or if your suggestion impacts other codes. Address anything it impacts.

Involve your organization:

  • Inform your leadership that you wish to submit suggestions for changes. You may want to gather input from other stakeholders and submit comments on proposed Addenda as an organization. Legal and/or compliance departments may want to looped in on suggestions and their outcomes. Ask your organizational leaders how to proceed. For instance, leadership may want one person to serve as the gatekeeper and submit all suggestions in batches, or conversely may permit staff to submit suggestions individually. Clarify if you are representing the organization versus operating as an individual.


Those submitting suggestions may receive an acknowledgment of receipt from NCHS, along with a statement that they will research the suggestion and bring it to a future C&M meeting if appropriate. Individuals may be asked to submit additional information. If your suggestions aren’t included in the inpatient prospective payment system (IPPS) final rule, you may want to resubmit them for further consideration. Stay positive even if you don’t hear back immediately.

Get involved
Please get involved either by personally emailing NHCS or by submitting suggestions through ACDIS’ Regulatory Committee. The Regulatory Committee has two purposes:

  • To educate CDI professionals on new rules and regulations and keep members informed about any changes that could affect CDI practices
  • To advocate for the CDI professional by providing commentary and information to various regulating agencies to support and defend the CDI practice and keep ACDIS members updated on those advocacy efforts

The Regulatory Committee regularly posts updates on the ACDIS website and in CDI Journal articles on questions that arise or on rules or regulations affecting the industry. Be sure to review these updates and articles to stay abreast on the latest changes.

Finally, don’t be shy about making suggestions or commenting on proposals. CDI staff are experts on clinical documentation practices and their influence on coded data. In addition, don’t be concerned about duplicating someone else’s submission. When multiple people send in the same concern, it can create a sense of urgency and lend more weight to the suggestion. Remember, our codes create data that’s used to ensure appropriate payment and the best possible patient care outcomes. A clean code set is easier to use, making our CDI and coding jobs easier and helping us to produce accurate data. By taking time to get involved, we create better information for healthcare in the future.

About the author and featured professionals:
Piper is the inpatient coding educator for SSM Health System, based in St. Louis, Missouri. She has a passion for helping others improve their coding knowledge and skills. In her current role, she provides education for coders at 17 hospitals in four states. Piper is the coding roundtable coordinator for the Missouri Health Information Management Association (MoHIMA), has prepared educational materials for AHIMA, and has served on the American Hospital Association’s Coding Clinic Advisory Board. Contact her at kay.

While writing this article, Piper had help from the following contributors:

  • Marion Gentul, RHIA, CCS, from Elsevier
  • Anita Schmidt, BS, RHIA, a clinical technical editor, coding solutions, at Optum360
  • Brigid T. Caffrey, BA, BA, MS, CCS, CDIP, an HIM and CAC-CDI product capability consultant, NLP innovation, at Optum360
  • Darlene Hyman, RHIA, CCS, COC, a coding education specialist at University of Maryland Health Services
  • Amber Davidson, RHIT, CCS, CCS-P, a health information data specialist at the Children’s Hospital Association
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