Excludes1 pair

E76.3 vs Q77-

E76.3 and Q77 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 Q77
mucopolysaccharidosis (E76.0-E76.3)
E76.3

Mucopolysaccharidosis, unspecified

BillableUnspecified
Chapter 4
Endocrine, nutritional and metabolic diseases
Section
E70-E88
Indexed under
  • Mucopolysaccharidosis
  • Cardiopathy › mucopolysaccharidosis
  • Mucopolysaccharidosis › cardiopathy
Q77

Osteochondrodysplasia with defects of growth of tubular bones and spine

Not billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q65-Q79

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