A50.2 vs A53.9
A50.2 and A53.9 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on A53.9
syphilis NOS under two years of age (A50.2)
A50.2
Early congenital syphilis, unspecified
BillableUnspecified
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A50-A64
Use when the record says
- Congenital syphilis NOS less than two years after birth.
Indexed under
- Syphilis, syphilitic › congenital › early, or less than 2 years after birth NEC (acquired)
A53.9
Syphilis, unspecified
BillableUnspecified
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A50-A64
Use when the record says
- Infection due to Treponema pallidum NOS
- Syphilis (acquired) NOS
Indexed under
- Syphilis, syphilitic (acquired)
- Syphilis, syphilitic › conjugal (acquired)
- Syphilis, syphilitic › due to blood transfusion (acquired)
- Syphilis, syphilitic › general (acquired)
- Syphilis, syphilitic › organic (acquired)
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027