Excludes1 pair
F84.0 vs F84.2
F84.0 and F84.2 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 F84.2
Autistic disorder (F84.0)
F84.0
Autistic disorder
Billable
- Chapter 5
- Mental, Behavioral and Neurodevelopmental disorders
- Section
- F80-F89
Use when the record says
- Autism spectrum disorder
- Infantile autism
- Infantile psychosis
- Kanner's syndrome
Indexed under
- Autism, autistic (childhood) (infantile)
- Autism, autistic › spectrum disorder
- Disorder › autistic
- Disorder › autism spectrum
- Psychosis, psychotic › childhood
F84.2
Rett's syndrome
Billable
- Chapter 5
- Mental, Behavioral and Neurodevelopmental disorders
- Section
- F80-F89
Indexed under
- Rett's disease or syndrome
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