A51
Non-billableEarly syphilis
Early syphilis
This is a header/category code. For billing purposes, use a more specific child code from the list below.
Coding Notes
Includes
Conditions included under this code
- diseases generally recognized as communicable or transmissible
Excludes 1
Codes that cannot be used together with this code (mutual exclusion)
- certain localized infections - see body system-related chapters
- •nonspecific and nongonococcal urethritisN34.1
- •Reiter's diseaseM02.3
Excludes 2
Conditions not included here, but the patient may have both
- •carrier or suspected carrier of infectious diseaseZ22
- •infectious and parasitic diseases complicating pregnancy, childbirth and the puerperiumO98
- •infectious and parasitic diseases specific to the perinatal periodP35-P39
- •influenza and other acute respiratory infectionsJ00-J22
- •human immunodeficiency virus [HIV] diseaseB20
Use Additional Code
Additional codes that should follow this code
Child Codes (7)
ICD-11 Equivalents(1)
ICD-11 Equivalents
View full mappingCorresponding ICD-11 codes from the WHO crosswalk mapping
Also Known As / Clinical Terms(2)
Frequently Asked Questions
What is the ICD-10 code for early syphilis?
The ICD-10-CM code for early syphilis is A51. The full clinical description is "Early syphilis". A51 is a non-billable header code. Use a more specific child code for billing purposes.
What does ICD-10 code A51 mean?
ICD-10-CM code A51 represents “Early syphilis”. It is classified under Chapter 1: Certain Infectious and Parasitic Diseases and is a non-billable header code. Use a more specific child code for billing purposes.
Is A51 a billable code?
No, A51 is a non-billable header code. You need to use one of its more specific child codes for billing. There are 7 child codes under A51.
What chapter is A51 in?
A51 is in Chapter 1: Certain Infectious and Parasitic Diseases (codes A00-B99).
What codes cannot be used with A51?
A51 has Excludes1 notes indicating codes that cannot be used together with it, including: certain localized infections - see body system-related chapters; nonspecific and nongonococcal urethritis (N34.1); Reiter's disease (M02.3-).
What are the subcategories under A51?
A51 has 7 child codes, including: 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), and 3 more.
Are additional codes required with A51?
Yes, when using A51, also report: resistance to antimicrobial drugs (Z16.-).
What are the UMLS CUIs for A51?
A51 is linked to 1 UMLS Concept Unique Identifier: C0348148. The UMLS (Unified Medical Language System) integrates multiple biomedical vocabularies maintained by the U.S. National Library of Medicine.
How does A51 relate to ICF functioning codes?
ICF (International Classification of Functioning, Disability and Health) codes describe how conditions like early syphilis affect a person's functioning — body functions, activities, participation, and environmental factors. AutoICD provides ICF Core Sets for 12+ conditions and can map clinical text to ICF categories automatically. Browse the ICF directory to explore functioning codes.
What is the ICD-11 equivalent of A51?
A51 maps to the ICD-11 code: 1A61.Z (Early syphilis, unspecified).
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Includes SNOMED Clinical Terms® (SNOMED CT®) used by permission of SNOMED International. Includes content from the UMLS Metathesaurus, courtesy of the U.S. National Library of Medicine.