G04.02 vs T88.1
G04.02 (Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis) compared with T88.1 (Other complications following immunization, not elsewhere classified), 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. T88.1 carries an Excludes2 note covering G04.02: “postimmunization encephalitis (G04.02)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
Side by side
| G04.02Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis | T88.1Other complications following immunization, not elsewhere classified | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | G00-G99 — Diseases of the Nervous System (G00-G99) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Postimmunization acute disseminated encephalomyelitis (ADEM) is a billable ICD-10-CM diagnosis code (G04.02). | Other complications following immunization, not elsewhere classified is a non-billable ICD-10-CM category code (T88.1). |
| 7th character | — | The appropriate 7th character is to be added to each code from category T88 |
| Includes | acute ascending myelitis meningoencephalitis meningomyelitis Encephalitis, post immunization | Generalized vaccinia Rash following immunization |
| Use additional code | code to identify the vaccine (T50.A-, T50.B-, T50.Z-) | code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5) code(s) to identify the specified condition resulting from the complication code to identify devices involved and details of circumstances (Y62-Y82) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources