A83 vs A92.3

A83 (Mosquito-borne viral encephalitis) compared with A92.3 (West Nile virus infection), from the official CMS tabular data. Both may be reported when both conditions are documented (Excludes2).

Can these codes be reported together?

Yes, when both are documented. A83 carries an Excludes2 note covering A92.3: “West Nile fever (A92.3-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

Yes, when both are documented. A83 carries an Excludes2 note covering A92.3: “West Nile virus (A92.3-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

Side by side

	A83Mosquito-borne viral encephalitis	A92.3West Nile virus infection
Billing status	Non-billable header Report instead: A83.0, A83.1, A83.2, A83.3, A83.4	Non-billable header Report instead: A92.30, A92.31, A92.32, A92.39
Classification	A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99)	A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99)
Definition	Mosquito-borne viral encephalitis is a non-billable ICD-10-CM category code (A83).	West Nile virus infection is a non-billable ICD-10-CM category code (A92.3).
Includes	mosquito-borne viral meningoencephalitis	West Nile fever

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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources