T65.854A (Toxic effect of medetomidine, undetermined, initial encounter) compared with T65.854D (Toxic effect of medetomidine, undetermined, subsequent encounter), from the official CMS tabular data. T65.854A and T65.854D 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. T65.854A and T65.854D 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.
| T65.854AToxic effect of medetomidine, undetermined, initial encounter | T65.854DToxic effect of medetomidine, undetermined, subsequent encounter | |
|---|---|---|
| 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) |
| 7th character | The appropriate 7th character is to be added to each code from category T65 | The appropriate 7th character is to be added to each code from category T65 |
| Use additional code | code to identify associated manifestations, such as: bradycardia NOS (R00.1) somnolence, stupor and coma (R40.-) | code to identify associated manifestations, such as: bradycardia NOS (R00.1) somnolence, stupor and coma (R40.-) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources