Q18.4 — Macrostomia
Q18.4 is a billable, specific ICD-10-CM code for macrostomia. It is valid for submission on a claim.
Other codes that can never be billed with Q18.4
These codes carry an Excludes1 note pointing at Q18.4. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading Q18.4 alone.
- Q38Other congenital malformations of tongue, mouth and pharynx
Risk adjustment
Q18.4 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
Q18.4 is named in 2 Medicare coverage policies — 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A54111Billing and Coding: Speech Language Pathology (SLP) Services: Communication Disorders
- A57204Billing and Coding: MRI and CT Scans of the Head and Neck
How Q18.4 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to Q18.4.
- Macrostomia(congenital)
- Meloschisis
Related codes at this level
Codes that share Q18. If Q18.4 is not quite right, the correct code is usually one of these.
- Q18.0Sinus, fistula and cyst of branchial cleft
- Q18.1Preauricular sinus and cyst
- Q18.2Other branchial cleft malformations
- Q18.3Webbing of neck
- Q18.5Microstomia
- Q18.6Macrocheilia
- Q18.7Microcheilia
- Q18.8Other specified congenital malformations of face and neck
- Q18.9Congenital malformation of face and neck, unspecified
Questions about Q18.4
- Is Q18.4 a billable ICD-10-CM code?
- Yes. Q18.4 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does Q18.4 sit in the tabular list?
- Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Congenital malformations of eye, ear, face and neck (Q10-Q18).