Q91
Q91 — Trisomy 18 and Trisomy 13
Non-billable headerICD-10-CM
Q91 is a non-billable header ICD-10-CM code for trisomy 18 and trisomy 13. It cannot be billed on its own: choose one of the more specific child codes below.
Other codes that can never be billed with Q91
These codes carry an Excludes1 note pointing at Q91. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading Q91 alone.
- Q92Other trisomies and partial trisomies of the autosomes, not elsewhere classified
Risk adjustment
Q91 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Code to one of these instead Q91
8 child codes. Green means billable.
- Q91.0Trisomy 18, nonmosaicism (meiotic nondisjunction)
- Q91.1Trisomy 18, mosaicism (mitotic nondisjunction)
- Q91.2Trisomy 18, translocation
- Q91.3Trisomy 18, unspecified
- Q91.4Trisomy 13, nonmosaicism (meiotic nondisjunction)
- Q91.5Trisomy 13, mosaicism (mitotic nondisjunction)
- Q91.6Trisomy 13, translocation
- Q91.7Trisomy 13, unspecified
Questions about Q91
- Is Q91 a billable ICD-10-CM code?
- No. Q91 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
- Where does Q91 sit in the tabular list?
- Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Chromosomal abnormalities, not elsewhere classified (Q90-Q99).