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A64 vs N34.3

A64 (Unspecified sexually transmitted disease) compared with N34.3 (Urethral syndrome, unspecified), 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 N34.3 lists A64 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and chapter.A64 is “Unspecified sexually transmitted disease”; N34.3 is “Urethral syndrome, unspecified”. A64 sits in A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99); N34.3 in N00-N99 — Diseases of the Genitourinary System (N00-N99).

Registry fact

Can these codes be reported together?

Yes, when both are documented.N34.3 lists A64 under Excludes2: “urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. A64 carries 2 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.N34.3’s tabular entry: “urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)”. The note covers A64.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

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

Is one a parent or header code?

No.Both are billable codes, and neither contains the other.

Registry fact

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

N34.3
Urethral syndrome, unspecified
↔
A64
Unspecified sexually transmitted disease

What we found

Yes, when both are documented.N34.3 carries an Excludes2 note covering A64: “urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)”

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
A64

Unspecified sexually transmitted disease

N34.3

Urethral syndrome, unspecified

StatusSame for both
Billable
Excludes1Differs
A64
  • nonspecific and nongonococcal urethritis (N34.1)
  • Reiter's disease (M02.3-)
N34.3

None at this code

Excludes2Differs
A64
  • human immunodeficiency virus [HIV] disease (B20)
N34.3
  • Reiter's disease (M02.3-)
  • urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)
  • urethrotrigonitis (N30.3-)
  • urinary infection (complicating):
  • abortion or ectopic or molar pregnancy (O00-O07, O08.8)
  • pregnancy, childbirth and the puerperium (O23.-, O75.3, O86.2-)
Use additional codeDiffers
A64

None at this code

N34.3
  • code (B95-B97), to identify infectious agent.
CategoryDiffers
A64

Is itself a category

N34.3

N34 Urethritis and urethral syndrome

ChapterDiffers
A64

A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99)

N34.3

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

No Code first, Code also, Includes 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, notes every code shares are dimmed.

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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