ICD-10 Spotlight: Know the codes (Coding Convention/Guideline: Excludes1 and Excludes2, and Borderline Diagnosis Codes)

November 1, 2012

Each month, IBC will feature an example of how ICD-9 codes will translate to ICD-10 codes. We will present coding examples from different specialties and popular disease categories to demonstrate the granularity that the new ICD-10 code set will provide.

CODING CONVENTION/GUIDELINE: Excludes1 and Excludes2, and Borderline Diagnosis Codes

Similar to ICD-9, there are coding conventions, general guidelines, and chapter-specific guidelines in ICD-10. These conventions and guidelines are rules and instructions that must be followed to classify and assign the most appropriate code. As with ICD-9, adherence to these guidelines is required under the Health Insurance Portability and Accountability Act (HIPAA). Many of the conventions and guidelines in ICD-9 are the same in ICD-10. This article will focus on a new Coding Convention: Excludes1 and Excludes2, and a new General Coding Guideline: Borderline Diagnosis Codes.

Excludes1 and Excludes2

As in ICD-9, a variety of notes appear in both the Alphabetic Index and Tabular List of ICD-10. These types of notes consist of inclusion notes, excludes notes, code first notes, use additional code notes, and cross reference notes. ICD-10 incorporates two types of excludes notes: Excludes1 and Excludes2. Each type of note has a different definition for use but are similar in that they indicate codes excluded from each other are independent of each other.


A type 1 Excludes note is a pure excludes note. It means "NOT CODED HERE!" It corresponds with what the current ICD-9 Excludes note indicates. An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 note is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. K51.4 - Inflammatory polyps of colon EXCLUDES1: adenomatous polyp of colon (D12.6) polyposis of colon (D12.6) polyps of colon NOS (K63.5)


A type 2 Excludes note represents "Not included here." An Excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate. J37.1 - Chronic laryngotracheitis EXCLUDES2: acute laryngotracheitis (J04.2) acute tracheitis (J04.1)

Borderline Diagnosis*

If the provider documents a "borderline" diagnosis at the time of discharge, the diagnosis is coded as confirmed, unless the classification provides a specific entry. If a borderline condition has a specific index entry in ICD-10, it should be coded as such. Since borderline conditions are not uncertain diagnoses, no distinction is made between the care setting (inpatient versus outpatient). Examples of Specific Borderline Entries: F60.3 Borderline personality disorder R41.83 Borderline intellectual functioning H40.021 Open angle with borderline findings, high-risk, right eye

*Whenever the documentation is unclear regarding a borderline condition, coders are encouraged to query for clarification.

For additional information related to the IBC transition to ICD-10, please visit the ICD-10 section of our website. On this site you will also find other examples of how ICD-9 codes will translate to ICD-10 codes in the ICD-10 Spotlight: Know the codes booklet.