Q91: Trisomy 18 and Trisomy 13
Codes under Q91 (Trisomy 18 and Trisomy 13). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| Q91.0 | Trisomy 18, nonmosaicism (meiotic nondisjunction) | ✓ |
| Q91.0 | Trisomy 18, nonmosaicism (meiotic nondisjunction) | ✓ |
| Q91.1 | Trisomy 18, mosaicism (mitotic nondisjunction) | ✓ |
| Q91.1 | Trisomy 18, mosaicism (mitotic nondisjunction) | ✓ |
| Q91.2 | Trisomy 18, translocation | ✓ |
| Q91.2 | Trisomy 18, translocation | ✓ |
| Q91.3 | Trisomy 18, unspecified | ✓ |
| Q91.3 | Trisomy 18, unspecified | ✓ |
| Q91.4 | Trisomy 13, nonmosaicism (meiotic nondisjunction) | ✓ |
| Q91.4 | Trisomy 13, nonmosaicism (meiotic nondisjunction) | ✓ |
| Q91.5 | Trisomy 13, mosaicism (mitotic nondisjunction) | ✓ |
| Q91.5 | Trisomy 13, mosaicism (mitotic nondisjunction) | ✓ |
| Q91.6 | Trisomy 13, translocation | ✓ |
| Q91.6 | Trisomy 13, translocation | ✓ |
| Q91.7 | Trisomy 13, unspecified | ✓ |
| Q91.7 | Trisomy 13, unspecified | ✓ |
Frequently asked questions
What is ICD-10-CM code Q91?
Q91 is an ICD-10-CM category covering Trisomy 18 and Trisomy 13. It contains 16 more specific diagnosis codes, 16 of which are billable.
Is Q91 a billable code?
No — Q91 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example Q91.0 — Trisomy 18, nonmosaicism (meiotic nondisjunction)). 16 of the 16 codes under Q91 are billable.
What codes fall under Q91?
Q91 includes Q91.0, Q91.0, Q91.1, Q91.1, Q91.2, plus 11 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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