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Q90.9

Q90.9Down syndrome, unspecified

Billable / specific codeICD-10-CMPOA exempt

Q90.9 is a billable, specific ICD-10-CM code for down syndrome, unspecified. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Trisomy 21 NOS

Risk adjustment

Q90.9 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

Q90.9 is named in 3 Medicare coverage policies 3 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A54111Billing and Coding: Speech Language Pathology (SLP) Services: Communication Disorders
  • A56781Billing and Coding: Transthoracic Echocardiography (TTE)
  • A56781Billing and Coding: Transthoracic Echocardiography (TTE)

How Q90.9 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to Q90.9.

  • Down syndrome
  • SyndromeDown
  • Trisomy21(partial)
  • Syndrometrisomy21

Related codes at this level

Codes that share Q90. If Q90.9 is not quite right, the correct code is usually one of these.

Questions about Q90.9

Is Q90.9 a billable ICD-10-CM code?
Yes. Q90.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does Q90.9 sit in the tabular list?
Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Chromosomal abnormalities, not elsewhere classified (Q90-Q99).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.