Q17 vs Q18.1
Q17 and Q18.1 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 Q17
preauricular sinus (Q18.1)
Q17
Other congenital malformations of ear
Not billable
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q10-Q18
Q18.1
Preauricular sinus and cyst
Billable
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q10-Q18
Use when the record says
- Fistula of auricle, congenital
- Cervicoaural fistula
Indexed under
- Cyst › ear (colloid) (mucous) (simple) (retention)
- Cyst › preauricular (colloid) (mucous) (simple) (retention)
- Fistula › cervical, lateral (cutaneous)
- Fistula › cervicoaural (cutaneous)
- Fistula › preauricular (cutaneous)
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