ICD-10-CM 2027
ICD-10 code for Tertiary syphilis
From the official ICD-10-CM alphabetic index entry “Syphilis, syphilitic (acquired) › tertiary”. Page updated September 29, 2026.
About coding Tertiary syphilis
The ICD-10-CM code for Tertiary syphilis is A52.9 (Late syphilis, unspecified). The official index lists 5 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on A52.9.
Within A52, choose A52.9 (unspecified) only when documentation doesn't support a more specific option: cardiovascular and cerebrovascular syphilis (A52.0), symptomatic neurosyphilis (A52.1), Asymptomatic neurosyphilis (A52.2), neurosyphilis, unspecified (A52.3), other symptomatic late syphilis (A52.7) and latent (A52.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 867 (Other Infectious and Parasitic Diseases Diagnoses with MCC, relative weight 2.1859), DRG 868 (Other Infectious and Parasitic Diseases Diagnoses with CC, relative weight 1.0235) and DRG 869 (Other Infectious and Parasitic Diseases Diagnoses without CC/MCC, relative weight 0.6787), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific Tertiary syphilis codes (official index)
Common questions about Tertiary syphilis ICD-10 codes
What is the ICD-10 code for Tertiary syphilis?
- A52.9 — Late syphilis, unspecified. More specific codes apply when the documentation supports them: A52.79, A52.00, A52.3, A52.79 and others below.
What is the ICD-10 code for cardiovascular tertiary syphilis?
- A52.00 — Cardiovascular syphilis, unspecified.
What is the ICD-10 code for central nervous system tertiary syphilis?
- A52.3 — Neurosyphilis, unspecified.
What is the ICD-10 code for multiple nec tertiary syphilis?
- A52.79 — Other symptomatic late syphilis.
Is A52.9 billable?
- Yes. A52.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A52.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A52.9 as a principal diagnosis.
Is A52.9 a CC or MCC?
- No. A52.9 is neither a CC nor an MCC under MS-DRG v44.0.