DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

Q91 Trisomy 18 and Trisomy 13

  • Header · not billable

Q91 is not billable. The category heads 8 billable codes in FY2027: the 8 codes directly below it.

Index → code

  • Trisomy (syndrome)13 (partial) → Q91.7
  • Trisomy (syndrome)18 (partial) → Q91.3
  • Syndrometrisomy13 → Q91.7

Where it sits

  1. Chapter 17 Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1)
  2. Q90-Q99 Chromosomal abnormalities, not elsewhere classified (Q90-Q99)
  3. Q91 Trisomy 18 and Trisomy 13
Billable codes
8
Subdivisions
8
CC / MCC codes
8 / 0
HCC V28 codes
0
New FY2027
0
Index entries
22

Codes in Q91

  1. Q91.0
    Trisomy 18, nonmosaicism (meiotic nondisjunction)
    BillableCCExempt
  2. Q91.1
    Trisomy 18, mosaicism (mitotic nondisjunction)
    BillableCCExempt
  3. Q91.2
    Trisomy 18, translocation
    BillableCCExempt
  4. Q91.3
    Trisomy 18, unspecified
    BillableCCExempt
  5. Q91.4
    Trisomy 13, nonmosaicism (meiotic nondisjunction)
    BillableCCExempt
  6. Q91.5
    Trisomy 13, mosaicism (mitotic nondisjunction)
    BillableCCExempt
  7. Q91.6
    Trisomy 13, translocation
    BillableCCExempt
  8. Q91.7
    Trisomy 13, unspecified
    BillableCCExempt

CC/MCC: as a secondary diagnosis, unless the principal diagnosis is on the code’s PDX exclusion list (MS-DRG v44 Appendix C; list on the code card).

Sources of each column.

Instructions

Notes that also apply

Block Q90-Q99 instructions (Excludes2 1): printed on the block page.

Chapter 17 instructions (Notes 1, Excludes2 1): printed on the chapter 17 page.

Index entries

  • Trisomy (syndrome)18 (partial) → Q91.3
  • Trisomy (syndrome)13 (partial) → Q91.7
  • Trisomy (syndrome)18 (partial)meiotic nondisjunction → Q91.0
  • Trisomy (syndrome)18 (partial)mitotic nondisjunction → Q91.1
  • Trisomy (syndrome)18 (partial)mosaicism → Q91.1
  • Translocationtrisomy18 → Q91.2
  • Trisomy (syndrome)18 (partial)translocation → Q91.2
  • Syndrometrisomy18 → Q91.3
  • Trisomy (syndrome)13 (partial)meiotic nondisjunction → Q91.4
  • Trisomy (syndrome)13 (partial)mitotic nondisjunction → Q91.5
  • Trisomy (syndrome)13 (partial)mosaicism → Q91.5
  • Translocationtrisomy13 → Q91.6
  • Trisomy (syndrome)13 (partial)translocation → Q91.6
  • Syndrometrisomy13 → Q91.7
  • Syndrometrisomy18meiotic nondisjunction → Q91.0
  • Syndrometrisomy18mitotic nondisjunction → Q91.1
  • Syndrometrisomy18mosaicism → Q91.1
  • Syndrometrisomy18translocation → Q91.2
  • Syndrometrisomy13meiotic nondisjunction → Q91.4
  • Syndrometrisomy13mitotic nondisjunction → Q91.5
  • Syndrometrisomy13mosaicism → Q91.5
  • Syndrometrisomy13translocation → Q91.6

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy