Q99
⚠ Non-billable
Other chromosome abnormalities, not elsewhere classified
ICD-10-CM · FY2026 · Congenital Malformations, Deformations and Chromosomal Abnormalities
Code
Q99
System
ICD-10-CM
Billable
No — use specific code
Effective
FY2026
Chapter
Congenital Malformations, Deformations and Chromosomal Abnormalities
Source
CMS / CDC NCHS
⚠ Verify before billing. Confirm against the current CMS/NCHS ICD-10-CM files and your payer's rules before claims submission.
Frequently asked questions
What is ICD-10 code Q99?
ICD-10-CM code Q99 represents Other chromosome abnormalities, not elsewhere classified. It is a non-billable header code requiring a more specific subcategory in the Congenital Malformations, Deformations and Chromosomal Abnormalities chapter, effective October 1, 2025 – September 30, 2026.
Is Q99 billable?
No. Q99 is a non-billable header. Select a more specific subcategory for claims submission.
What chapter is Q99 in?
Q99 belongs to the Congenital Malformations, Deformations and Chromosomal Abnormalities chapter (Q00–Q99) of ICD-10-CM.
Related codes in the Q99 category
Q99.0
Chimera 46, XX/46, XY
Billable
Q99.1
46, XX true hermaphrodite
Billable
Q99.2
Fragile X chromosome
Billable
Q99.8
Other specified chromosome abnormalities
Non-billable
Q99.9
Chromosomal abnormality, unspecified
Billable
Q99.81
Usher syndrome
Non-billable
Q99.89
Other specified chromosome abnormalities
Billable
Q99.811
Usher syndrome, type 1
Billable
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