I88.1 vs L04
I88.1 and L04 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. The distinction is acute vs chronic.
The official note, declared on L04
chronic or subacute lymphadenitis, except mesenteric (I88.1)
I88.1
Chronic lymphadenitis, except mesenteric
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I80-I89
Use when the record says
- Adenitis
- Lymphadenitis
Indexed under
- Adenitis › chronic, unspecified site
- Adenitis › subacute, unspecified site
- Lymphadenitis › chronic
- Lymphadenitis › subacute, unspecified site
- Adenitis › axillary › chronic or subacute
L04
Acute lymphadenitis
Not billable
- Chapter 12
- Diseases of the skin and subcutaneous tissue
- Section
- L00-L08
Use when the record says
- abscess (acute) of lymph nodes, except mesenteric
- acute lymphadenitis, except mesenteric
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