T79.4XXA (Traumatic shock, initial encounter) compared with T79.4XXD (Traumatic shock, subsequent encounter), from the official CMS tabular data. T79.4XXA and T79.4XXD code the same injury at a different phase of treatment. MedCoder-derived
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. T79.4XXA and T79.4XXD 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.
| T79.4XXATraumatic shock, initial encounter | T79.4XXDTraumatic shock, subsequent encounter | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | S00-T88 — Injury, poisoning and certain other consequences of external causes | S00-T88 — Injury, poisoning and certain other consequences of external causes |
| Definition | Traumatic shock, initial encounter is a billable ICD-10-CM diagnosis code (T79.4A). | Traumatic shock, subsequent encounter is a billable ICD-10-CM diagnosis code (T79.4D). |
| 7th character | The appropriate 7th character is to be added to each code from category T79 | The appropriate 7th character is to be added to each code from category T79 |
| Includes | Shock (immediate) (delayed) following injury | Shock (immediate) (delayed) following injury |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources