FY2027
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Excludes1 pair

I88.9 vs L04-

I88.9 and L04 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on L04
lymphadenitis NOS (I88.9)
I88.9

Nonspecific lymphadenitis, unspecified

BillableUnspecified
Chapter 9
Diseases of the circulatory system
Section
I80-I89
Use when the record says
  • Lymphadenitis NOS
Indexed under
  • Lymphadenitis
  • Adenitis › axillary
  • Adenitis › cervical
  • Adenitis › groin
  • Adenitis › inguinal
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