ICDcodes.org
FY2027

Q18.5 vs Q38

Q18.5 and Q38 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 official note, declared on Q38
microstomia (Q18.5)
Q18.5

Microstomia

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q10-Q18
Indexed under
  • Microstomia (congenital)
Q38

Other congenital malformations of tongue, mouth and pharynx

Not billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q38-Q45

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