Excludes1 pair
A33 vs A35
A33 and A35 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on A35
tetanus neonatorum (A33)
A33
Tetanus neonatorum
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A30-A49
Indexed under
- Omphalitis › tetanus
- Tetanus, tetanic › neonatorum
- Trismus › neonatorum
- Trismus › newborn
A35
Other tetanus
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A30-A49
Use when the record says
- Tetanus NOS
Indexed under
- Tetanus, tetanic (cephalic) (convulsions)
- Radiculomyelitis › toxic, due to › Clostridium tetani
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