F81.0 vs R48.0
F81.0 and R48.0 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 F81.0
alexia NOS (R48.0)
F81.0
Specific reading disorder
Billable
- Chapter 5
- Mental, Behavioral and Neurodevelopmental disorders
- Section
- F80-F89
Use when the record says
- 'Backward reading'
- Developmental dyslexia
- Specific learning disorder, with impairment in reading
- Specific reading retardation
Indexed under
- Backward reading (dyslexia)
- Mirror writing
- Strephosymbolia
- Alexia › developmental
- Blindness › word (acquired) (congenital) (both eyes)
R48.0
Dyslexia and alexia
Billable
- Chapter 18
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Section
- R47-R49
Indexed under
- Alexia
- Dyslexia
- Agraphia › with alexia (absolute)
- Alexia › secondary to organic lesion
- Disorder › reading (of)
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