Excludes1 pair

G35- vs G37.3

G35 and G37.3 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 G37.3
multiple sclerosis (G35-)
G35

Multiple sclerosis

Not billable
Chapter 6
Diseases of the nervous system
Section
G35-G37
G37.3

Acute transverse myelitis in demyelinating disease of central nervous system

Billable
Chapter 6
Diseases of the nervous system
Section
G35-G37
Use when the record says
  • Acute transverse myelitis NOS
  • Acute transverse myelopathy
Indexed under
  • Myelitis › transverse (in demyelinating diseases of central nervous system)
  • Myelopathy › transverse, acute

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