Excludes1 pair

F43.0 vs R53.8-

F43.0 and R53.8 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 R53.8
combat exhaustion and fatigue (F43.0)
F43.0

Acute stress reaction

Billable
Chapter 5
Mental, Behavioral and Neurodevelopmental disorders
Section
F40-F48
Use when the record says
  • Acute crisis reaction
  • Acute reaction to stress
  • Combat and operational stress reaction
  • Combat fatigue
  • Crisis state
  • Psychic shock
Indexed under
  • Battle exhaustion
  • Combat fatigue
  • Shellshock (current)
  • Crisis › acute reaction
  • Crisis › state (acute reaction)
R53.8

Other malaise and fatigue

Not billable
Chapter 18
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Section
R50-R69

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