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E66 ICD-10-CM Code: Overweight and obesity

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

Coding at a Glance

Tabular directives
4 Excludes2 · 1 use-additional code · 1 code-first instruction

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for E66 in the official ICD-10-CM tabular list, quoted as published.

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

Excludes2 — Not Included Here

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

Code First

Underlying conditions that must be sequenced before this code.

  • obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-)

Coder workflow for E66

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

Before you code E66

  1. E66 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).

    ReviewE66.0, E66.1, E66.2, E66.3, E66.8, E66.9

    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 E66?
    Yes → Select that code and continue the checks below on its own page.
    No → E66 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewE66.0, E66.1, E66.2, E66.3, E66.8, E66.9

  2. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then E66.
    No → Continue; do not add an underlying condition the record does not document.

    ReviewO99.21

Consider E66. Then work the Use Additional Code 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 underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).
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 E66(4 notes)

    Coding workflow: The conditions named in this note are not included in E66. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareE23.6, E88.2, Q87.11

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

  • Code First — sequencing check(1 note)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before E66. Do not add an underlying condition the record does not document.

    ReviewO99.21

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

  • Use Additional Code — after identifying E66(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with E66 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewZ68.5

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

Coding decision scenarios

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

Documentation: The underlying condition the Code First note names is documented alongside this condition.

Coding question: How are the two sequenced?

Path: Review the Code First note.

Reason: The underlying condition is sequenced first and the manifestation follows (Guidelines I.A.13).

ReviewO99.21

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

Coding question: Is a second code reported with E66?

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).

ReviewZ68.5

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

Overweight and obesity is a non-billable ICD-10-CM category code (E66). 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.

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 4: Endocrine, Nutritional, and Metabolic Diseases (E00 -E89)

b. Obesity The obesity codes in category E66, Overweight and obesity, include codes related to the cause of obesity, such as drug-induced obesity (E66.1), and codes related to effects of obesity, such as code E66.2, Morbid (severe) obesity with alveolar hypoventilation. There are other codes related to obesity in other categories of the classification, such as E88.82, Obesity due to disruption of MC4R pathway; and codes in fifth character subcategory O99.21, Obesity complicating pregnancy, childbirth, and the puerperium.

Decision Points

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

  1. Sequencing: 1 Code First instruction — the underlying condition is sequenced before this code when present. See the Code First notes
  2. 1 Use Additional Code instruction — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  3. 4 Excludes2 entries — 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 E66 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 1 Excludes1 note: R63.5 — Abnormal weight gain.

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: Z99.3 — Dependence on wheelchair.

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.

Referenced by 2 Use Additional Code instructions across 2 chapters: E88.81 — Metabolic syndrome and other insulin resistance, O99.21 — Obesity complicating pregnancy, childbirth, and the puerperium.

These codes instruct coders to additionally report this code when it applies.

Contextual Map

Every relationship of E66 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 E66 with these 9 related codes in Claim Check

Hierarchy

Excludes2

Code First

Use Additional Code

  • Z68 — Body mass index [BMI][Use Additional Code]: “code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • Z68.5 — Body mass index [BMI] pediatric[Use Additional Code]: “code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes1 notes

Referenced by Code First instructions

Referenced by Use Additional Code instructions

Nearest codes (13)

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 E66 be billed directly?

No. E66 (Overweight and obesity) 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
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section 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. "E66 — Overweight and obesity." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/e66-overweight-and-obesity

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Overweight and obesity

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 E66 in its code family, with their registry titles.