R51.9 vs R52
R51.9 and R52 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 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 (s)
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 (s)
- Pain › generalized NOS (s)
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