U.S. ICD-10-CM · FY 2027

A51 ICD-10-CM Code: Early syphilis

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

A51

Early syphilis

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where A51 sits

  1. 1

    Chapter 1

    Certain infectious and parasitic diseases (A00-B99)

  2. 2

    Section

    Infections with a predominantly sexual mode of transmission (A50-A64)

  3. 3

    Category A51

    Early syphilis

  4. 4

    Code A51

    Early syphilis

More specific choices

Codes under A51

A51 is a non-billable category. Choose the child code that best matches the documented diagnosis.

A51.0

Primary genital syphilis

A51.1

Primary anal syphilis

A51.2

Primary syphilis of other sites

A51.3

Secondary syphilis of skin and mucous membranes

A51.4

Other secondary syphilis

A51.5

Early syphilis, latent

A51.9

Early syphilis, unspecified

Documentation details

Notes for this code

Inclusion terms

No inclusion terms are listed for A51.

Code first

No “code first” instruction is listed for A51.

Use additional code

No “use additional code” instruction is listed for A51.

Excludes1

Conditions that should not be reported together with this code.

No Excludes1 note is listed for A51.

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for A51.

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

Publisher

Vero Scribe Inc.

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code A51 mean?

A51 is the FY 2027 U.S. ICD-10-CM code for “Early syphilis.”

Is A51 a billable or specific ICD-10-CM code?

No. A51 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is A51 located in ICD-10-CM?

A51 is listed in Chapter 1, Certain infectious and parasitic diseases (A00-B99), within Infections with a predominantly sexual mode of transmission (A50-A64) (A50–A64), under category A51, Early syphilis.

What coding notes are listed for A51?

No inclusion terms are listed for A51 in this reference record. No code-first instruction is listed. No Excludes1 note is listed. No Excludes2 note is listed.

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