Understanding the difference between Excludes1 and Excludes2 notes is one of the most critical skills in ICD-10 coding. As defined in the official ICD-10 coding guidelines, these notes appear throughout the classification and have very different meanings that directly impact whether codes can be used together.
Excludes1 - "NOT CODED HERE"
An Excludes1 note indicates a "pure" exclusion - meaning that the code excluded should never be used at the same time as the code above the Excludes1 note. The two conditions cannot occur together by definition.
Critical Rule
Excludes1 codes are mutually exclusive. If you code one, you cannot code the other for the same encounter. Doing so will likely result in claim denial.
Examples of Excludes1
- Congenital absence of organ vs acquired absence of organ
- Acute vs chronic forms of the same condition (when they can't coexist)
- Different stages of disease progression that are mutually exclusive
Excludes2 - "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. If both conditions are documented, both codes may be assigned.
Key Point
Excludes2 simply means the excluded condition is a separate diagnosis. Both codes can be reported together when both conditions are documented.
Examples of Excludes2
- Asthma with COPD - both can exist and be coded
- Diabetes with hypertension - separate conditions, both coded
- Related but distinct conditions that commonly occur together
Side-by-Side Comparison
| Feature | Excludes1 | Excludes2 |
|---|---|---|
| Meaning | "NOT CODED HERE" | "NOT INCLUDED HERE" |
| Can codes be used together? | No - mutually exclusive | Yes - if both conditions exist |
| Conditions relationship | Cannot occur together | Can occur together |
| Claim impact | Will likely be denied | Both accepted if documented |
Validate Against ICD 10 CM Coding Guidelines
Our Code Auditor automatically detects Excludes1 conflicts based on official FY2026 guidelines.
Look up ICD 10 CM codes to find diagnosis codes before validation.
Best Practices
- Always check Excludes notes when assigning codes
- For Excludes1: Choose the most appropriate code based on documentation
- For Excludes2: Code both conditions if both are documented
- Use validation tools to catch Excludes1 violations before claim submission
Excludes1 violations are one of the most common ICD-10 coding errors that lead to claim denials. Our Code Auditor can help identify these issues automatically.