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I10-I1A vs O13

I10-I1A (Hypertensive diseases (I10-I1A)) compared with O13 (Gestational [pregnancy-induced] hypertension without significant proteinuria), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because I10-I1A lists O13 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and chapter.I10-I1A is “Hypertensive diseases (I10-I1A)”; O13 is “Gestational [pregnancy-induced] hypertension without significant proteinuria”. I10-I1A sits in I00-I99 — Diseases of the Circulatory System (I00-I99); O13 in O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A).

Registry fact

Can these codes be reported together?

Yes, when both are documented.I10-I1A lists O13 under Excludes2: “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.I10-I1A’s tabular entry: “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”. The note covers O13.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

Both are headers.Both are non-billable headers, and neither contains the other.

Registry fact

Nothing found in 3 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. I10-I1A carries 2 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

I10-I1A
Hypertensive diseases (I10-I1A)
↔
O13
Gestational [pregnancy-induced] hypertension without significant proteinuria

What we found

Yes, when both are documented.I10-I1A carries an Excludes2 note covering O13: “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
I10-I1A

Hypertensive diseases (I10-I1A)

O13

Gestational [pregnancy-induced] hypertension without significant proteinuria

StatusDiffers
I10-I1A
Non-billable header

A header is not reported on a claim; a code beneath it is.

O13
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: O13.1, O13.2, O13.3, O13.4, O13.5

Excludes1Differs
I10-I1A
  • neonatal hypertension (P29.2)
  • primary pulmonary hypertension (I27.0)
O13

None at this code

Excludes2Differs
I10-I1A
  • hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)
O13

None at this code

Use additional codeDiffers
I10-I1A
  • code to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)
O13

None at this code

CategoryDiffers
I10-I1A

I10 Essential (primary) hypertension

O13

Is itself a category

ChapterDiffers
I10-I1A

I00-I99 — Diseases of the Circulatory System (I00-I99)

O13

O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A)

IncludesDiffers
I10-I1A

None at this code

O13
  • gestational hypertension NOS
  • transient hypertension of pregnancy

No Code first, Code also and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources