Excludes1 pair

E88.A vs R64

E88.A and R64 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 E88.A
cachexia NOS (R64)
E88.A

Wasting disease (syndrome) due to underlying condition

Billable
Chapter 4
Endocrine, nutritional and metabolic diseases
Section
E70-E88
Use when the record says
  • Cachexia due to underlying condition
Indexed under
  • Disease, diseased › wasting NEC
  • Syndrome › wasting due to underlying condition (syndrome)
  • Wasting › disease (syndrome)
  • Cachexia › due to › malnutrition
  • Cachexia › due to › underlying condition
R64

Cachexia

Billable
Chapter 18
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Section
R50-R69
Indexed under
  • Cachexia
  • Emaciation
  • Inanition
  • Cachexia › cancerous
  • Cachexia › malignant

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