T78.19XA (Other adverse food reactions, not elsewhere classified, initial encounter) compared with T78.19XS (Other adverse food reactions, not elsewhere classified, sequela), from the official CMS tabular data. T78.19XA and T78.19XS code the same injury at a different phase of treatment.
Same underlying diagnosis, different encounter phase.
The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.
Source: ICD-10-CM Official Guidelines, Section I.C.19.a
Same injury, other encounter phase. T78.19XA and T78.19XS code the same injury at a different phase of treatment, set by the 7th character.
The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.
| T78.19XAOther adverse food reactions, not elsewhere classified, initial encounter | T78.19XSOther adverse food reactions, not elsewhere classified, sequela | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Other adverse food reactions, not elsewhere classified, initial encounter is a billable ICD-10-CM diagnosis code (T78.19A). | Other adverse food reactions, not elsewhere classified, sequela is a billable ICD-10-CM diagnosis code (T78.19S). |
| 7th character | The appropriate 7th character is to be added to each code from category T78 | The appropriate 7th character is to be added to each code from category T78 |
| Use additional code | code to identify the type of reaction, if applicable | code to identify the type of reaction, if applicable |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources