2027 ICD-10-CM Diagnosis Code Q91Trisomy 18 and Trisomy 13

ICD-10-CM Codes›Q00-Q99›Q90-Q99›Q91

ICD-10-CM Q91
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q91 is a non-billable ICD-10-CM category code for trisomy 18 and Trisomy 13, so it cannot be submitted on claims. Use a more specific code from this category instead, such as Q91.0, Q91.1, Q91.2, and Q91.3.

Code Identity

ICD-10-CM Code
Q91
Billable Status
No — Non-Billable Category
Code Describes
Trisomy 18 and Trisomy 13
Short Description
Trisomy 18 and Trisomy 13
Same as the full description in the CMS dataset.
Chapter
Q90-Q99
Chromosomal abnormalities, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ90-Q99Chromosomal abnormalities, not elsewhere classified
CategoryQ91Trisomy 18 and Trisomy 13
This CodeQ91Trisomy 18 and Trisomy 13

Specific Coding for Trisomy 18 and Trisomy 13Overview

Non-specific codes like Q91 require more characters. Use one of these billable codes instead:

  • Use Q91.0 for Trisomy 18, nonmosaicism (meiotic nondisjunction)

  • Use Q91.1 for Trisomy 18, mosaicism (mitotic nondisjunction)

  • Use Q91.2 for Trisomy 18, translocation

  • Use Q91.3 for Trisomy 18, unspecified

  • Use Q91.4 for Trisomy 13, nonmosaicism (meiotic nondisjunction)

  • Use Q91.5 for Trisomy 13, mosaicism (mitotic nondisjunction)

  • Use Q91.6 for Trisomy 13, translocation

  • Use Q91.7 for Trisomy 13, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q91: its own notes plus those printed at block Q90-Q99 and Chapter 17. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block Q90-Q99 Chromosomal abnormalities, not elsewhere classified applies to 74 codes
  • mitochondrial metabolic disorders (E88.4-)
From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • inborn errors of metabolism (E70-E88)

Notes

General instructions on how these codes are used.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • Codes from this chapter are not for use on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Q91, its category, or a range that includes it.

Excludes1 4

These codes carry an Excludes1 note naming Q91: they are not reported together with it, unless the two conditions are unrelated.

  • E25 Adrenogenital disorders
    chromosomal abnormalities (Q90-Q99) names Q90-Q99, which includes this code
  • Block Q50-Q56 Congenital malformations of genital organs
    syndromes associated with anomalies in the number and form of chromosomes (Q90-Q99) names Q90-Q99, which includes this code
  • Q92 Other trisomies and partial trisomies of the autosomes, not elsewhere classified
    trisomies of chromosomes 13, 18, 21 (Q90-Q91) names Q90-Q91, which includes this code
  • Z15 Genetic susceptibility to disease
    chromosomal anomalies (Q90-Q99) names Q90-Q99, which includes this code

Code First 1

These codes say to code first a condition named in the note, and Q91 is one of the conditions named.

  • D84.81 Immunodeficiency due to conditions classified elsewhere
    chromosomal abnormalities (Q90-Q99) names Q90-Q99, which includes this code

Patient EducationClinical

Genetic Disorders

Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.

The full article covers:

  • What are genetic disorders?
  • What causes genetic disorders?
  • What are the types of genetic disorders?
  • What are the different ways a genetic disorder can be inherited?
  • How are genetic disorders diagnosed?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q91Overview

What is the ICD-10 code for trisomy 18 and Trisomy 13?

Q91 is the ICD-10-CM category for trisomy 18 and Trisomy 13, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is Q91 (Trisomy 18 and Trisomy 13) a billable code?

No. This is a category header that groups the codes for trisomy 18 and Trisomy 13, and headers cannot be submitted on claims. Claims for trisomy 18 and Trisomy 13 need a more specific code from this category, such as Q91.0, Q91.1, and Q91.2.