A84 vs B91
A84 (Tick-borne viral encephalitis) compared with B91 (Sequelae of poliomyelitis), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. A84 carries an Excludes1 note covering B91: “sequelae of poliomyelitis (B91)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| A84Tick-borne viral encephalitis | B91Sequelae of poliomyelitis | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99) | A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99) |
| Definition | Tick-borne viral encephalitis is a non-billable ICD-10-CM category code (A84). | Sequelae of poliomyelitis is a billable ICD-10-CM diagnosis code (B91). |
| Includes | tick-borne viral meningoencephalitis | — |
| Code first | — | condition resulting from (sequela) the infectious or parasitic disease |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources