T56.5X4A (Toxic effect of zinc and its compounds, undetermined, initial encounter) compared with T56.5X4S (Toxic effect of zinc and its compounds, undetermined, sequela), from the official CMS tabular data. T56.5X4A and T56.5X4S 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. T56.5X4A and T56.5X4S 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.
| T56.5X4AToxic effect of zinc and its compounds, undetermined, initial encounter | T56.5X4SToxic effect of zinc and its compounds, undetermined, 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 zinc and its compounds, undetermined, initial encounter is a billable ICD-10-CM diagnosis code (T56.5X4A). | Toxic effect of zinc and its compounds, undetermined, sequela is a billable ICD-10-CM diagnosis code (T56.5X4S). |
| 7th character | The appropriate 7th character is to be added to each code from category T56 | The appropriate 7th character is to be added to each code from category T56 |
| Includes | toxic effects of fumes and vapors of metals toxic effects of metals from all sources, except medicinal substances | toxic effects of fumes and vapors of metals toxic effects of metals from all sources, except medicinal substances |
| Use additional code | code to identify any retained metal foreign body, if applicable (Z18.0-, T18.1-) code(s): for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) | code to identify any retained metal foreign body, if applicable (Z18.0-, T18.1-) 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