Q04.9 — Congenital malformation of brain, unspecified
Is Q04.9 billable?
Yes, but Q04.9 is an unspecified code. Q04.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, Q04.9 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting Q04.9 — the more specific alternatives are listed below.
Q04.9 at a glance
| Code | Q04.9 |
|---|---|
| Description | Congenital malformation of brain, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does Q04.9 group to?
Q04.9 sits in MDC 01 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 091Other Disorders of Nervous System with MCCmedical
- 092Other Disorders of Nervous System with CCmedical
- 093Other Disorders of Nervous System without CC/MCCmedical
How is Q04.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Q04.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Cyclencephaly
- Anomaly, anomalous › brain (congenital) (unspecified type)
- Anomaly, anomalous › cerebral (congenital) (unspecified type)
- Anomaly, anomalous › dura (congenital) (unspecified type)
- Deformity › brain
- Distortion › brain (s) (congenital)
- Malformation › brain (congenital)
- Malformation › cerebral (congenital)
- Deformity › cerebral, acquired › congenital
- Disease, diseased › brain › congenital
- Lesion › brain › congenital (s) (nontraumatic)
- Malformation › dura › brain (congenital)
Inclusion terms
Alternative wording in documentation that is classified to Q04.9.
- Congenital anomaly NOS of brain
- Congenital deformity NOS of brain
- Congenital disease or lesion NOS of brain
- Multiple anomalies NOS of brain, congenital
Excludes1 — never code together — inherited from Q04
The conditions below can never be reported together with Q04.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from Chapter 17
The conditions below are not part of Q04.9, but a patient may have both at the same time. When documentation supports it, Q04.9 and the excluded code may both be reported.
- inborn errors of metabolism (E70-E88)
How long has Q04.9 existed?
Q04.9 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.