ICD10

ICD-10 Code Q99.8: Other specified chromosome abnormalities

Q99.8 is an ICD-10 diagnosis entry used to group records related to Other specified chromosome abnormalities. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA0).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA0).

When is it used?

  • May be used when a clinician documents other specified chromosome abnormalities in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
  • This entry may represent a broader category rather than the most specific billable code.

Code hierarchy

chapter
17Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA0)
block
Q90-Q99Chromosomal abnormalities, not elsewhere classified
category
Q99Other chromosome abnormalities, not elsewhere classified
currentQ99

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Coding guidelines

Compatibility

Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.
Legacy codes
Q99.8
Replacement codes
Q99.89 — Other specified chromosome abnormalities

Common synonyms

Other specified chromosome abnormalities

Frequently asked questions

Code details

CodeQ99.8
SystemICD10
Display nameOther specified chromosome abnormalities
ChapterCongenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA0)
BlockChromosomal abnormalities, not elsewhere classified

Flags

BillableNo
Valid clinical useNo

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Abnormal, abnormality, abnormalitiesAbnormal, abnormality, abnormalitiesAdditionalAnomaly, anomalous(congenital) (unspecified type)SyndromeTranslocation
See also
Trisomy

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code Q99.8 for Other specified chromosome abnormalities | HealthAssure