Excludes1 pair
F09 vs F29
F09 and F29 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 F09
psychosis NOS (F29)
F09
Unspecified mental disorder due to known physiological condition
BillableUnspecified
- Chapter 5
- Mental, Behavioral and Neurodevelopmental disorders
- Section
- F01-F09
Use when the record says
- Mental disorder NOS due to known physiological condition
- Organic brain syndrome NOS
- Organic mental disorder NOS
- Organic psychosis NOS
- Symptomatic psychosis NOS
Indexed under
- Deficiency, deficient › cognitive
- Disorder › cognitive
- Organic › brain syndrome
- Organic › mental disorder
- Organic › psychosis
F29
Unspecified psychosis not due to a substance or known physiological condition
BillableUnspecified
- Chapter 5
- Mental, Behavioral and Neurodevelopmental disorders
- Section
- F20-F29
Use when the record says
- Psychosis NOS
- Unspecified schizophrenia spectrum and other psychotic disorder
Indexed under
- Psychosis, psychotic
- Disorder › schizophrenia spectrum and other psychotic disorder
- Psychosis, psychotic › confusional
- Psychosis, psychotic › nonorganic
- Schizophrenia, schizophrenic › spectrum and other psychotic disorder
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