Q91 Trisomy 18 and Trisomy 13

Category / Non-billable header 8 subcodes

Block: Chromosomal abnormalities, not elsewhere classified (Q90-Q99)

Subcodes

Subcodes are listed below for reference. Detail pages are not available for chapters 11–22.

Code Description Billable
Q91..0 Trisomy 18, nonmosaicism (meiotic nondisjunction) Yes
Q91..1 Trisomy 18, mosaicism (mitotic nondisjunction) Yes
Q91..2 Trisomy 18, translocation Yes
Q91..3 Trisomy 18, unspecified Yes
Q91..4 Trisomy 13, nonmosaicism (meiotic nondisjunction) Yes
Q91..5 Trisomy 13, mosaicism (mitotic nondisjunction) Yes
Q91..6 Trisomy 13, translocation Yes
Q91..7 Trisomy 13, unspecified Yes

Last reviewed: September 2026