T51.1X3A (Toxic effect of methanol, assault, initial encounter) compared with T51.1X3S (Toxic effect of methanol, assault, sequela), from the official CMS tabular data. T51.1X3A and T51.1X3S 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. T51.1X3A and T51.1X3S 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.
| T51.1X3AToxic effect of methanol, assault, initial encounter | T51.1X3SToxic effect of methanol, 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 methanol, assault, initial encounter is a billable ICD-10-CM diagnosis code (T51.1X3A). | Toxic effect of methanol, assault, sequela is a billable ICD-10-CM diagnosis code (T51.1X3S). |
| 7th character | The appropriate 7th character is to be added to each code from category T51 | The appropriate 7th character is to be added to each code from category T51 |
| Use additional code | code(s): for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) personal history of foreign body fully removed (Z87.821) | code(s): for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) personal history of foreign body fully removed (Z87.821) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources