2021 ICD-10-CM Code Q99

Other chromosome abnormalities, not elsewhere classified

Version 2021
Non-Billable Code

Not Valid for Submission

Q99 is a "header" nonspecific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of other chromosome abnormalities, not elsewhere classified. The code is NOT valid for the year 2021 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

ICD-10:Q99
Short Description:Other chromosome abnormalities, not elsewhere classified
Long Description:Other chromosome abnormalities, not elsewhere classified

Code Classification

Specific Coding for Other chromosome abnormalities, not elsewhere classified

Header codes like Q99 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10 codes with a higher level of specificity when coding for other chromosome abnormalities, not elsewhere classified:

  • Q99.0 - Chimera 46, XX/46, XY
  • Q99.1 - 46, XX true hermaphrodite
  • Q99.2 - Fragile X chromosome
  • Q99.8 - Other specified chromosome abnormalities
  • Q99.9 - Chromosomal abnormality, unspecified

Information for Patients


Genetic Disorders

Genes are the building blocks of heredity. They are passed from parent to child. They hold DNA, the instructions for making proteins. Proteins do most of the work in cells. They move molecules from one place to another, build structures, break down toxins, and do many other maintenance jobs.

Sometimes there is a mutation, a change in a gene or genes. The mutation changes the gene's instructions for making a protein, so the protein does not work properly or is missing entirely. This can cause a medical condition called a genetic disorder.

You can inherit a gene mutation from one or both parents. A mutation can also happen during your lifetime.

There are three types of genetic disorders:

Genetic tests on blood and other tissue can identify genetic disorders.

NIH: National Library of Medicine


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Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)