FY2027
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Excludes1 pair

E13- vs H20.0-

E13 and H20.0 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 H20.0
iridocyclitis, iritis, uveitis (due to) (in) diabetes mellitus (E08-E13 with .39)
E13

Other specified diabetes mellitus

Not billable
Chapter 4
Endocrine, nutritional and metabolic diseases
Section
E08-E13
Use when the record says
  • 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
H20.0

Acute and subacute iridocyclitis

Not billable
Chapter 7
Diseases of the eye and adnexa
Section
H15-H22
Use when the record says
  • Acute anterior uveitis
  • Acute cyclitis
  • Acute iritis
  • Subacute anterior uveitis
  • Subacute cyclitis
  • Subacute iritis
Indexed under
  • Iridocyclitis › acute

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