2027 ICD-10-CM Diagnosis Code Q99.0Chimera 46, XX/46, XY

ICD-10-CM Codes›Q00-Q99›Q90-Q99›Q99

ICD-10-CM Q99.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q99.0 is a billable ICD-10-CM diagnosis code for chimera 46, XX/46, XY. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 729 through 730, 742 through 743, 760 through 761. The code is exempt from POA reporting. Coders also document this condition as chimera. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Chromosomal abnormalities.

Code Identity

ICD-10-CM Code
Q99.0
Billable Status
Yes — Valid for Submission
Code Describes
Chimera 46, XX/46, XY
Short Description
Chimera 46, XX/46, XY
Same as the full description in the CMS dataset.
Parent Code
Q99
Other chromosome abnormalities, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ90-Q99Chromosomal abnormalities, not elsewhere classified
CategoryQ99Other chromosome abnormalities, not elsewhere classified
This CodeQ99.0Chimera 46, XX/46, XY

Present on Admission (POA)Billing

Q99.0 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Chromosomal abnormalities, not elsewhere classified (Q90-Q99).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chimera
  • Chimera 46, XX; 46, XY

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q99.0: 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.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Chimera 46, XX/46, XY true hermaphrodite

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 Q99.0, its category, or a range that includes it.

Excludes1 5

These codes carry an Excludes1 note naming Q99.0: they are not reported together with it, unless the two conditions are unrelated.

  • Q56 Indeterminate sex and pseudohermaphroditism
    chimera 46,XX/46,XY true hermaphrodite (Q99.0)
  • 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
  • Q56 Indeterminate sex and pseudohermaphroditism
    pseudohermaphroditism with specified chromosomal anomaly (Q96-Q99) names Q96-Q99, 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 Q99.0 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

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL009
Chromosomal abnormalities
Default principal diagnosis: inpatient Yes · outpatient Yes

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.

Convert Q99.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
758.81 Oth cond due to sex chrm
Approximate The match is approximate rather than exact.

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 Q99.0Overview

What is the ICD-10 code for chimera 46, XX/46, XY?

The ICD-10-CM code for chimera 46, XX/46, XY is Q99.0 (sometimes written as Q990). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q99.0 (Other chromosome abnormalities, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chimera 46, XX/46, XY on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Q99.0 group to?

When chimera 46, XX/46, XY is the principal diagnosis on an inpatient stay, it groups to MS-DRG 742, 729, 743, 760, 761, 730, with relative weights from 0.6595 to 1.8448 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q99.0 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for chimera 46, XX/46, XY on inpatient claims. The code appears in the Chromosomal abnormalities, not elsewhere classified (Q90-Q99) range of the CMS exempt list.

What is the ICD-9 equivalent of Q99.0?

Under the General Equivalence Mappings, chimera 46, XX/46, XY converts to ICD-9-CM 758.81 (oth cond due to sex chrm). The mapping is approximate, so confirm the match fits the documentation.