S40.849A (External constriction of unspecified upper arm, initial encounter) compared with S40.849S (External constriction of unspecified upper arm, sequela), from the official CMS tabular data. S40.849A and S40.849S 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. S40.849A and S40.849S 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.
| S40.849AExternal constriction of unspecified upper arm, initial encounter | S40.849SExternal constriction of unspecified upper arm, sequela | |
|---|---|---|
| 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 | External constriction of unspecified upper arm, initial encounter is a billable ICD-10-CM diagnosis code (S40.849A). | External constriction of unspecified upper arm, sequela is a billable ICD-10-CM diagnosis code (S40.849S). |
| 7th character | The appropriate 7th character is to be added to each code from category S40 | The appropriate 7th character is to be added to each code from category S40 |
| Includes | injuries of axilla injuries of scapular region | injuries of axilla injuries of scapular region |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources