Q91Header code — not billable
Trisomy 18 and Trisomy 13
- Chapter
- 17. Congenital malformations, deformations and chromosomal abnormalities
- Category
- Q91
- Effective date
- October 1, 2026
Related codes in category Q91
Q91.0Trisomy 18, nonmosaicism (meiotic nondisjunction)YesQ91.1Trisomy 18, mosaicism (mitotic nondisjunction)YesQ91.2Trisomy 18, translocationYesQ91.3Trisomy 18, unspecifiedYesQ91.4Trisomy 13, nonmosaicism (meiotic nondisjunction)YesQ91.5Trisomy 13, mosaicism (mitotic nondisjunction)YesQ91.6Trisomy 13, translocationYesQ91.7Trisomy 13, unspecifiedYes
Frequently asked questions
What is ICD-10 code Q91?
Q91 is an ICD-10-CM diagnosis code for Trisomy 18 and Trisomy 13.
Is Q91 a billable code?
No. Q91 is a category/header code, not billable on its own — use one of its more specific child codes instead.
What ICD-10-CM chapter is Q91 in?
Q91 falls under Chapter 17: Congenital malformations, deformations and chromosomal abnormalities.
When did Q91 become effective?
Q91 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to Q91?
Q91 belongs to category Q91, which includes 8 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.