A53.9 — Syphilis, unspecified
Is A53.9 billable?
Yes, but A53.9 is an unspecified code. A53.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, A53.9 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting A53.9 — the more specific alternatives are listed below.
More specific alternatives
A53.9 at a glance
| Code | A53.9 |
|---|---|
| Description | Syphilis, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does A53.9 group to?
A53.9 sits in MDC 18 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 867Other Infectious and Parasitic Diseases Diagnoses with MCCmedical
- 868Other Infectious and Parasitic Diseases Diagnoses with CCmedical
- 869Other Infectious and Parasitic Diseases Diagnoses without CC/MCCmedical
How is A53.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to A53.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Syphilis, syphilitic (acquired)
- Syphilis, syphilitic › conjugal (acquired)
- Syphilis, syphilitic › due to blood transfusion (acquired)
- Syphilis, syphilitic › general (acquired)
- Syphilis, syphilitic › organic (acquired)
- Positive › VDRL › with signs or symptoms - code by site and stage under Syphilis
Excludes1 — never code together
The conditions below can never be reported together with A53.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- syphilis NOS under two years of age (A50.2)
Inclusion terms
Alternative wording in documentation that is classified to A53.9.
- Infection due to Treponema pallidum NOS
- Syphilis (acquired) NOS
Excludes1 — never code together — inherited from A50-A64
The conditions below can never be reported together with A53.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from Chapter 1
Report an additional code alongside A53.9 to fully describe the condition. A53.9 is sequenced first.
- code to identify resistance to antimicrobial drugs (Z16.-)
Excludes2 — not included here — inherited from Chapter 1
The conditions below are not part of A53.9, but a patient may have both at the same time. When documentation supports it, A53.9 and the excluded code may both be reported.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
Excludes2 — not included here — inherited from A50-A64
The conditions below are not part of A53.9, but a patient may have both at the same time. When documentation supports it, A53.9 and the excluded code may both be reported.
- human immunodeficiency virus [HIV] disease (B20)
How long has A53.9 existed?
A53.9 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with A53.9?
ICD-10-CM declares these codes mutually exclusive with A53.9 — exactly one of each pair can be correct for a given encounter.