Q90.9 — Down syndrome, unspecified
Is Q90.9 billable?
Yes, but Q90.9 is an unspecified code. Q90.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, Q90.9 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 Q90.9 — the more specific alternatives are listed below.
Q90.9 at a glance
| Code | Q90.9 |
|---|---|
| Description | Down syndrome, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does Q90.9 group to?
Q90.9 sits in MDC 19 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 884Organic Disturbances and Intellectual Disabilitymedical
How is Q90.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Q90.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Down syndrome
- Syndrome › Down
- Trisomy › 21 (syndrome)
- Syndrome › trisomy › 21
Inclusion terms
Alternative wording in documentation that is classified to Q90.9.
- Trisomy 21 NOS
Use additional code — inherited from Q90
Report an additional code alongside Q90.9 to fully describe the condition. Q90.9 is sequenced first.
- code(s) to identify any associated degree of intellectual disabilities (F70-F79)
Excludes2 — not included here — inherited from Chapter 17
The conditions below are not part of Q90.9, but a patient may have both at the same time. When documentation supports it, Q90.9 and the excluded code may both be reported.
- inborn errors of metabolism (E70-E88)
Excludes2 — not included here — inherited from Q90-Q99
The conditions below are not part of Q90.9, but a patient may have both at the same time. When documentation supports it, Q90.9 and the excluded code may both be reported.
- mitochondrial metabolic disorders (E88.4-)
Code also — inherited from Q90
Two codes may be needed to describe the condition fully. Whether Q90.9 is sequenced first depends on the reason for the encounter.
- associated physical condition(s), such as atrioventricular septal defect (Q21.2-)
How long has Q90.9 existed?
Q90.9 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.