All ICD10 Codes
A51Not billable, use a more specific code below

Early syphilis

In Infections with a predominantly sexual mode of transmission (A50-A64), chapter 1: Certain Infectious and Parasitic Diseases

15 billable codes under A51: 1 is an MCC, 9 are a CC; none map to an HCC.A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment.

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Instructional notes

Also applies, from Infections with a predominantly sexual mode of transmission (A50-A64)

These notes sit on A50-A64 and apply to every code under it, including A51.

Excludes1: not coded here, use a different code

  • nonspecific and nongonococcal urethritis (N34.1)
  • Reiter's disease (M02.3-)

Excludes2: not included here, code separately if applicable

  • human immunodeficiency virus [HIV] disease (B20)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.

Read Section I.C.1 (page 19)

All codes under A51

A51 can't be used on a claim. Pick a billable code below; grey headings group them.

A51 MS-DRGs

As the principal diagnosis, the billable codes under A51 group to these 28 MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Syphilis

Syphilis is a sexually transmitted infection (STI) caused by bacteria. It infects the genital area, lips, mouth, or anus of both men and women. You usually get syphilis from sexual contact with someone who has it. It can also pass from mother to baby during pregnancy.

Read more about syphilis on MedlinePlus

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.