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N90.81 vs Z91.138

N90.81 (Female genital mutilation status) compared with Z91.138 (Patient's unintentional underdosing of medication regimen for other reason), 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 Z91.138 lists N90.81 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named, billing status and chapter.N90.81 is “Female genital mutilation status”; Z91.138 is “Patient's unintentional underdosing of medication regimen for other reason”. N90.81 is a non-billable header; Z91.138 is billable. N90.81 sits in N00-N99 — Diseases of the Genitourinary System (N00-N99); Z91.138 in Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99).

Registry fact

Can these codes be reported together?

Yes, when both are documented.Z91.138 lists N90.81 under Excludes2: “female genital mutilation status (N90.81-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.Z91.138’s tabular entry: “female genital mutilation status (N90.81-)”. The note covers N90.81.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

One is a header.N90.81 is a non-billable header, but Z91.138 is not one of its subdivisions.

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. N90.81 carries 7 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

Z91.138
Patient's unintentional underdosing of medication regimen for other reason
↔
N90.81
Female genital mutilation status

What we found

Yes, when both are documented.Z91.138 carries an Excludes2 note covering N90.81: “female genital mutilation status (N90.81-)”

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
N90.81

Female genital mutilation status

Z91.138

Patient's unintentional underdosing of medication regimen for other reason

StatusDiffers
N90.81
Non-billable header

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

Report instead: N90.810, N90.811, N90.812, N90.813, N90.818

Z91.138
Billable
Excludes1Differs
N90.81
  • anogenital (venereal) warts (A63.0)
  • carcinoma in situ of vulva (D07.1)
  • condyloma acuminatum (A63.0)
  • current obstetric trauma (O70.-, O71.7-O71.8)
  • inflammation of vulva (N76.-)
  • severe dysplasia of vulva (D07.1)
  • vulvar intraepithelial neoplasm III [VIN III] (D07.1)
Z91.138

None at this code

Excludes2Differs
N90.81

None at this code

Z91.138
  • caregiver noncompliance with patient's medical treatment and regimen (Z91.A-)
  • contact with and (suspected) exposures hazardous to health (Z77.-)
  • exposure to pollution and other problems related to physical environment (Z77.1-)
  • female genital mutilation status (N90.81-)
  • occupational exposure to risk factors (Z57.-)
  • personal history of physical injury and trauma (Z87.81, Z87.82-)
Code firstDiffers
N90.81

None at this code

Z91.138
  • underdosing of medication (T36-T50) with fifth or sixth character 6
Code alsoDiffers
N90.81

None at this code

Z91.138
  • , if applicable, to identify underdosing of specific drug (T36-T50 with final character 6)
  • any follow-up examination (Z08-Z09)
CategoryDiffers
N90.81

N90 Other noninflammatory disorders of vulva and perineum

Z91.138

Z91 Personal risk factors, not elsewhere classified

ChapterDiffers
N90.81

N00-N99 — Diseases of the Genitourinary System (N00-N99)

Z91.138

Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99)

IncludesDiffers
N90.81
  • Female genital cutting status
Z91.138

None at this code

No Use additional code 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.

Edit this comparisonCheck a whole claim

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