P04.1 vs Q86.1
P04.1 and Q86.1 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 P04.1
fetal hydantoin syndrome (Q86.1)
P04.1
Newborn affected by other maternal medication
Not billable
- Chapter 16
- Certain conditions originating in the perinatal period
- Section
- P00-P04
Q86.1
Fetal hydantoin syndrome
Billable
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q80-Q89
Use when the record says
- Meadow's syndrome
Indexed under
- Meadow's syndrome
- Dysmorphism › hydantoin (due to)
- Fetus, fetal › hydantoin syndrome
- Syndrome › fetal › hydantoin
- Syndrome › malformation, congenital, due to › hydantoin
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