ICD-10-CM 2027
ICD-10 code for autosomes abnormal
From the official ICD-10-CM alphabetic index entry “Abnormal, abnormality, abnormalities › autosomes”. Page updated September 29, 2026.
About coding autosomes abnormal
The ICD-10-CM code for autosomes abnormal is Q99.9 (Chromosomal abnormality, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on Q99.9.
Within Q99, choose Q99.9 (Chromosomal abnormality, unspecified) only when documentation doesn't support a more specific option: Chimera 46, XX/46, XY (Q99.0), 46, XX true hermaphrodite (Q99.1), fragile X chromosome (Q99.2) and other specified chromosome abnormalities (Q99.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific autosomes abnormal codes (official index)
- fragile site Q95.5 — Individual with autosomal fragile site
Common questions about autosomes abnormal ICD-10 codes
What is the ICD-10 code for autosomes abnormal?
- Q99.9 — Chromosomal abnormality, unspecified. More specific codes apply when the documentation supports them: Q95.5.
What is the ICD-10 code for fragile site autosomes abnormal?
- Q95.5 — Individual with autosomal fragile site.
Is Q99.9 billable?
- Yes. Q99.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q99.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q99.9 as a principal diagnosis.
Is Q99.9 a CC or MCC?
- No. Q99.9 is neither a CC nor an MCC under MS-DRG v44.0.