F09 vs F29
F09 and F29 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 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 (of)
- 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 (of)
- 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