T63.423A (Toxic effect of venom of ants, assault, initial encounter) compared with T63.423S (Toxic effect of venom of ants, assault, sequela), from the official CMS tabular data. T63.423A and T63.423S 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. T63.423A and T63.423S 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.
| T63.423AToxic effect of venom of ants, assault, initial encounter | T63.423SToxic effect of venom of ants, assault, 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 | Toxic effect of venom of ants, assault, initial encounter is a billable ICD-10-CM diagnosis code (T63.423A). | Toxic effect of venom of ants, assault, sequela is a billable ICD-10-CM diagnosis code (T63.423S). |
| 7th character | The appropriate 7th character is to be added to each code from category T63 | The appropriate 7th character is to be added to each code from category T63 |
| Includes | bite or touch of venomous animal pricked or stuck by thorn or leaf | bite or touch of venomous animal pricked or stuck by thorn or leaf |
| Use additional code | code, if applicable, for anaphylactic shock (T78.2) code(s): for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) | code, if applicable, for anaphylactic shock (T78.2) code(s): for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources