FY2027
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Excludes1 pair

R51.9 vs R52

R51.9 and R52 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 R52
headache (R51.9)
R51.9

Headache, unspecified

BillableUnspecified
Chapter 18
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Section
R50-R69
Use when the record says
  • Facial pain NOS
Indexed under
  • Headache
  • Headache › chronic daily
  • Headache › daily chronic
  • Headache › nasal septum
  • Pain › face, facial
R52

Pain, unspecified

BillableUnspecified
Chapter 18
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Section
R50-R69
Use when the record says
  • Acute pain NOS
  • Generalized pain NOS
  • Pain NOS
Indexed under
  • Pain (s)
  • Pain › acute
  • Pain › generalized NOS

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