E13 vs L99
E13 and L99 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
Other specified diabetes mellitus
- Chapter 4
- Endocrine, nutritional and metabolic diseases
- Section
- E08-E13
- diabetes mellitus due to genetic defects of beta-cell function
- diabetes mellitus due to genetic defects in insulin action
- postpancreatectomy diabetes mellitus
- postprocedural diabetes mellitus
- secondary diabetes mellitus NEC
Other disorders of skin and subcutaneous tissue in diseases classified elsewhere
- Chapter 12
- Diseases of the skin and subcutaneous tissue
- Section
- L80-L99
- Amyloidosis › skin (generalized) (primary)
- Lichen › amyloidosis
- Degeneration, degenerative › cutis › amyloid
- Degeneration, degenerative › skin › amyloid
- Disease, diseased › skin › due to metabolic disorder NEC
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027