FY2027
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Excludes1 pair

Q40.1 vs Q79.0

Q40.1 and Q79.0 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 Q40.1
congenital diaphragmatic hernia (Q79.0)
Q40.1

Congenital hiatus hernia

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q38-Q45
Use when the record says
  • Congenital displacement of cardia through esophageal hiatus
Indexed under
  • Displacement, displaced › cardia through esophageal hiatus (congenital)
  • Hernia, hernial › hiatal › congenital
  • Hernia, hernial › paraesophageal › congenital
Q79.0

Congenital diaphragmatic hernia

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q65-Q79
Indexed under
  • Hernia, hernial › diaphragm, diaphragmatic › congenital
  • Defect, defective › diaphragm › congenital › with hernia
  • Defect, defective › diaphragm › congenital › gross (with hernia)

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