Excludes1 pair

M43.6 vs P15.2

M43.6 and P15.2 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 M43.6
torticollis due to birth injury (P15.2)
M43.6

Torticollis

Billable
Chapter 13
Diseases of the musculoskeletal system and connective tissue
Section
M40-M43
Indexed under
  • Grisel's disease
  • Torticollis (intermittent) (spastic)
  • Disease, diseased › Grisel's
  • Nasopharyngeal › torticollis
  • Rheumatic › torticollis
P15.2

Sternomastoid injury due to birth injury

Billable
Chapter 16
Certain conditions originating in the perinatal period
Section
P10-P15
Indexed under
  • Hematoma › sternocleidomastoid, birth injury
  • Hematoma › sternomastoid, birth injury
  • Birth › injury NOS › sternomastoid (hematoma)

These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.

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