Health Information Management

ICD-10-CM coding: Start with the structure

JustCoding News: Outpatient, March 21, 2012

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The transition to ICD-10-CM is coming. The only question is when. CMS is currently reviewing the implementation date that was originally set for October 1, 2013 and is expected to publish a new implementation date in April.

Despite the delay, coders and other HIM professionals must continue to prepare for the transition.
Coders must remember that the diagnostic conditions won't necessarily be new, says Shannon E. McCall, RHIA, CCS, CCS-P, CPC, CPC-I, CEMC, CCDS, director of coding and HIM at HCPro, Inc., in Danvers, MA. Instead of relying on memory for the appropriate codes, coders will need to manually look up codes (or use an encoder) to choose the correct code. This step will be necessary until coders become accustomed to the new system, says McCall.

To locate an ICD-10-CM code, coders should look up the main term in the Alphabetic Index or Table of Drugs and Chemicals, then verify the code assignment in the Tabular List, says McCall. Coders should also consider any instructional notes pertinent to the category of codes they assign.

Learn the structure of the new codes
Coders will need to adjust to the appearance of ICD-10-CM codes, as it differs significantly from ICD-9-CM codes.

Currently, ICD-9-CM codes consist of three to five digits. For example, ICD-9-CM code 490 denotes bronchitis, not specified as acute or chronic.

If a physician documents simple chronic bronchitis, coders can assign a four-digit code (491.0) that reflects the added specificity. If a physician documents obstructive chronic bronchitis with acute exacerbation, coders can report a five-digit code (491.21) to reflect the added severity.

ICD-10-CM codes, on the other hand, contain three to seven characters, where the first character is always a letter, the second is numeric, and characters three through seven can be alpha or numeric. As in ICD-9-CM, the first three characters of an ICD-10-CM code designate a category, McCall says.

The decimal point is used after the third character. The seventh character is used in certain chapters to provide information about the characteristics of the encounter.

For example, when a physician documents bronchitis, not specified as acute or chronic, coders should report ICD-10-CM code J40. Simple chronic bronchitis becomes J41.0.

Chronic obstructive bronchitis codes fall within the J44.- series in ICD-10-CM. For chronic obstructive pulmonary disease with acute exacerbation, coders should report ICD-10-CM code J44.1.
Some ICD-10-CM codes include greater detail and additional characters.

When looking at injuries and diseases of the musculoskeletal system, codes become even more specific. Codes for pneumococcal arthritis of the hand require seven ¬characters, with the seventh character indicating laterality (i.e., which hand is affected).

Laterality is a new convention in ICD-10-CM, McCall says. "It's something that is pretty easy to incorporate into the documentation. If a physician documents a fracture, it's not uncommon for the physician to include right or left in the documentation,” she adds.

Understand the role of characters 4–7
The fourth through seventh characters can vary by chapter and by disease. As an example, consider the meaning of characters four through seven in Chapter 13, Diseases of the Musculoskeletal System and Connective Tissue (M00–M99).

Characters four through six of codes within this range denote the etiology, anatomic site, and severity. The seventh character represents the visit, encounter, or sequelae for injuries and external causes. The meanings of the seventh character for ICD-10-CM codes vary across chapters and categories, says Sandy Nicholson, MA, RHIA, vice president of health information services for DCBA, Inc., a consulting firm in Atlanta.

Do not use the ICD-10-CM aftercare Z codes for aftercare for injuries, Nicholson says. Assign the acute injury code with the appropriate seventh character for subsequent encounter for this purpose.

Get to know the placeholder
Not every ICD-10-CM code with a seventh character has a sixth character—or even a fifth or fourth character for that matter. This frequently occurs with poisonings and injuries. The letter "x” serves as a placeholder when a code contains fewer than six characters and a seventh character applies, says Nicholson. The "x” also allows for future expansion of the codes.

When reporting ICD-10-CM codes, coders must add a placeholder so the seventh character is in the correct position. Without this placeholder to ensure characters appear in the correct positions, codes are invalid.

For example, a patient presents with an accidental poisoning by an antiallergic drug. For the initial encounter, coders should report ICD-10-CM code T45.0x1A. In this case, the x in the fifth position serves as a placeholder so that the sixth and seventh characters are in the correct position. If a coder inadvertently omits the placeholder, the resulting code would be T45.01A, which is invalid.

Coders should also note that an ICD-10-CM code can start with an X (i.e., codes X00–X99), McCall says.

For example, in code category X78.0, the X denotes the intention of an injury, exposure, etc. The X series of codes is part of Chapter 20: External Causes of Morbidity.

Note that the location of the X within a code matters. When X is in the fourth, fifth, and/or sixth character, it appears lowercase and is a placeholder. When X is at the beginning of the code, it is uppercase and indicates the chapter.

Not everything is changing in ICD-10-CM
The ICD-10-CM coding system includes some considerable changes from ICD-9-CM; however, some aspects will remain the same.

Outpatient coders will continue to use CPT® codes the same way they do currently, says Robert S. Gold, MD, CEO of DCBA, Inc., a consulting firm in Atlanta. The only aspect that will change is how the diagnosis is reported.

The terms that physicians use to document diagnoses and procedures won't change either, Gold adds. Coders will continue to see the same terminology in the medical record. The language that physicians use won't change to accommodate for the new codes, although coders should be prepared to query for additional information when necessary.

Most of the coding guidelines will also remain the same. The challenge for coders will be to apply the new guidelines when they contradict those that have been in place for many years, cautions Jennifer Avery, CCS, CPC-H, CPC, CPC-I, senior regulatory specialist with HCPro, Inc., in Danvers, MA.

"Coders are very structured people and they don't like it when guidelines change,” Avery says. "That's going to be a struggle [for some coders].”

Coders who code both inpatient and outpatient records will still need to remember which hat they're wearing, Avery says. As with ICD-9-CM, some of the ICD-10-CM guidelines vary depending on setting.

Note other similarities
Coders and other health information management (HIM) professionals generally focus on the ways in which ICD-10-CM is different from ICD-9-CM. This includes the number of codes, their length and appearance, the level of specificity, and the increased documentation requirements.

However, not everything is changing. For example, the index in ICD-10-CM will be structured similarly to the index in ICD-9-CM. ICD-10-CM indexes will include the Alphabetic Index of Diseases and Injuries, Alphabetic Index of External Causes, Table of Neoplasms, and Table of Drugs and Chemicals. The Alphabetic Index will be divided into two parts:

  • Index to Diseases and Injuries
  • Index to External Causes

The ICD-10-CM Tabular Index will retain the same hierarchical structure as ICD-9-CM. The chapters are structured similarly to ICD-9-CM with minor exceptions. For example, the sense organs (i.e., eye and ear) will move from the nervous system chapter to their own specific chapters.

In addition, many conventions (e.g., abbreviations, punctuation, and symbols) will retain the same meaning. Even though ICD-10-CM generally provides more detail, nonspecific codes (i.e., those that are unspecified or not otherwise specified) are available to use when providers don't include enough detail in the documentation to support more specific code assignment.

Parentheses will continue to enclose supplementary terms that may be present or absent in the statement of a disease or procedure. These are otherwise known as nonessential modifiers, says Kim Felix, RHIA, CCS, director of education with MECA, LLC, in Holland, PA.

Inclusion terms and includes notes carry the same meaning in ICD-10-CM as they do in ICD-9-CM (i.e., to clarify the content of the chapter, subchapter, category, or subdivision to which the terms apply), Felix says.

Throughout the ICD-9-CM tabular listing, notes describe the general content of the succeeding categories and provide instructions for assigning these codes. The same is true for ICD-10-CM.

In ICD-10-CM, "code first” notes will continue to alert coders that two codes are necessary to completely classify the condition. The term "and” will continue to mean "and/or” in both the Alphabetic Index and the tabular listing for ICD-10-CM.

Editor’s note: This article was originally published in the March issue of Briefings on APCs. E-mail your questions to Senior Managing Editor Michelle A. Leppert, CPC-A, at

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