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ICD-10-CM tabular list

Q90-Q99Chromosomal abnormalities, not elsewhere classified

ICD-10-CM codes Q90-Q99 cover chromosomal abnormalities, not elsewhere classified, within congenital malformations, deformations and chromosomal abnormalities. The block holds 88 codes across 9 categories, of which 74 are billable and 14 are header codes that cannot be submitted on a claim.

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

  • mitochondrial metabolic disorders (E88.4-)

What else to watch in Q90-Q99

  • 21 codes are named in Medicare coverage policies. An LCD or NCD lists them as supporting medical necessity, or explicitly as not supporting it. Which applies depends on the MAC for your state.

Categories in Q90-Q99

ICD-10-CMFY2026-Apr· effective April 1, 2026