S91.021A (Laceration with foreign body, right ankle, initial encounter) compared with S91.021S (Laceration with foreign body, right ankle, sequela), from the official CMS tabular data. S91.021A and S91.021S 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. S91.021A and S91.021S 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.
| S91.021ALaceration with foreign body, right ankle, initial encounter | S91.021SLaceration with foreign body, right ankle, 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 | Laceration with foreign body, right ankle, initial encounter is a billable ICD-10-CM diagnosis code (S91.021A). | Laceration with foreign body, right ankle, sequela is a billable ICD-10-CM diagnosis code (S91.021S). |
| 7th character | The appropriate 7th character is to be added to each code from category S91 | The appropriate 7th character is to be added to each code from category S91 |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources