Excludes1 pair

A92.5 vs P35.4

A92.5 and P35.4 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 A92.5
congenital Zika virus disease (P35.4)
A92.5

Zika virus disease

Billable
Chapter 1
Certain infectious and parasitic diseases
Section
A90-A99
Use when the record says
  • Zika virus fever
  • Zika virus infection
  • Zika NOS
Indexed under
  • Zika NOS
  • Disease, diseased › Zika virus
  • Fever › Zika virus
  • Infection, infected, infective › Zika virus
P35.4

Congenital Zika virus disease

Billable
Chapter 16
Certain conditions originating in the perinatal period
Section
P35-P39
Indexed under
  • Zika NOS › congenital
  • Disease, diseased › Zika virus › congenital
  • Infection, infected, infective › Zika virus › congenital

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