S83.401A (Sprain of unspecified collateral ligament of right knee, initial encounter) compared with S83.401S (Sprain of unspecified collateral ligament of right knee, sequela), from the official CMS tabular data. S83.401A and S83.401S 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. S83.401A and S83.401S 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.
| S83.401ASprain of unspecified collateral ligament of right knee, initial encounter | S83.401SSprain of unspecified collateral ligament of right knee, 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 | Sprain of unspecified collateral ligament of right knee, initial encounter is a billable ICD-10-CM diagnosis code (S83.401A). | Sprain of unspecified collateral ligament of right knee, sequela is a billable ICD-10-CM diagnosis code (S83.401S). |
| 7th character | The appropriate 7th character is to be added to each code from category S83 | The appropriate 7th character is to be added to each code from category S83 |
| Includes | avulsion of joint or ligament of knee laceration of cartilage, joint or ligament of knee sprain of cartilage, joint or ligament of knee traumatic hemarthrosis of joint or ligament of knee | avulsion of joint or ligament of knee laceration of cartilage, joint or ligament of knee sprain of cartilage, joint or ligament of knee traumatic hemarthrosis of joint or ligament of knee |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources