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Q90 ICD-10-CM Code: Down syndrome

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

Tabular directives
1 Excludes2 · 1 use-additional code · 1 code-also instruction

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for Q90 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on Q90 itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from Q90-Q99

Code Also

Additional codes that may be required to fully describe the encounter.

  • associated physical condition(s), such as atrioventricular septal defect (Q21.2-)

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code(s) to identify any associated degree of intellectual disabilities (F70-F79)

Coder workflow for Q90

MedCoder structured workflow — derived from this code’s own official record

Before you code Q90

  1. Q90 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewQ90.0, Q90.1, Q90.2, Q90.9

    See the relationships section · Guide: How to choose an ICD-10-CM code →

Choose the right path

  1. Does the documentation support one of the more specific codes beneath Q90?
    Yes → Select that code and continue the checks below on its own page.
    No → Q90 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewQ90.0, Q90.1, Q90.2, Q90.9

Consider Q90. Then work the Use Additional Code note and review the Code Also note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Excludes2 — not part of Q90(1 note)

    Coding workflow: The conditions named in this note are not included in Q90. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareE88.4

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying Q90(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with Q90 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    See the official tabular notes · Guidelines I.A.13

  • Code Also — related condition(1 note)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    ReviewQ21.2

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with Q90?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Down syndrome is a non-billable ICD-10-CM category code (Q90). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. 1 Use Additional Code instruction — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  3. 1 Excludes2 entry — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name Q90 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 11 Excludes1 notes across 3 chapters: E25 — Adrenogenital disorders, Q50 — Congenital malformations of ovaries, fallopian tubes and broad ligaments, Q50-Q56 — Congenital malformations of genital organs (Q50-Q56), Q51 — Congenital malformations of uterus and cervix, Q52 — Other congenital malformations of female genitalia, Q53 — Undescended and ectopic testicle, Q54 — Hypospadias, Q55 — Other congenital malformations of male genital organs, Q56 — Indeterminate sex and pseudohermaphroditism, Q92 — Other trisomies and partial trisomies of the autosomes, not elsewhere classified, Z15 — Genetic susceptibility to disease.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Code First instruction: D84.81 — Immunodeficiency due to conditions classified elsewhere.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Contextual Map

Every relationship of Q90 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run Q90 with these 17 related codes in Claim Check

Hierarchy

Excludes2

Use Additional Code

  • F70 — Mild intellectual disabilities[Use Additional Code]: “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F71 — Moderate intellectual disabilities[Use Additional Code]: “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F72 — Severe intellectual disabilities[Use Additional Code]: “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F73 — Profound intellectual disabilities[Use Additional Code]: “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F78 — Other intellectual disabilities[Use Additional Code]: “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F79 — Unspecified intellectual disabilities[Use Additional Code]: “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Code Also

  • Q21.2 — Atrioventricular septal defect[Code Also]: “associated physical condition(s), such as atrioventricular septal defect (Q21.2-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes1 notes (11)

Referenced by Code First instructions

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Can Q90 be billed directly?

No. Q90 (Down syndrome) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "Q90 — Down syndrome." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/q90-down-syndrome

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Down syndrome

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to Q90 in its code family, with their registry titles.