Q99.9 — Chromosomal abnormality, unspecified
Is Q99.9 billable?
Yes, but Q99.9 is an unspecified code. Q99.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, Q99.9 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 Q99.9 — the more specific alternatives are listed below.
More specific alternatives
Q99.9 at a glance
| Code | Q99.9 |
|---|---|
| Description | Chromosomal abnormality, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does Q99.9 group to?
Q99.9 sits in MDC 23 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.
- 951Other Factors Influencing Health Statusmedical
How is Q99.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Q99.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Abnormal, abnormality, abnormalities › autosomes
- Abnormal, abnormality, abnormalities › chromosome, chromosomal
- Anomaly, anomalous › chromosomes, chromosomal (congenital) (unspecified type)
- Syndrome › due to abnormality › chromosomal
Excludes2 — not included here — inherited from Chapter 17
The conditions below are not part of Q99.9, but a patient may have both at the same time. When documentation supports it, Q99.9 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 Q99.9, but a patient may have both at the same time. When documentation supports it, Q99.9 and the excluded code may both be reported.
- mitochondrial metabolic disorders (E88.4-)
How long has Q99.9 existed?
Q99.9 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.