T24.421D (Corrosion of unspecified degree of right knee, subsequent encounter) compared with T24.422D (Corrosion of unspecified degree of left knee, subsequent encounter), from the official CMS tabular data. T24.421D and T24.422D code the same condition on opposite sides. MedCoder-derived
Same condition; these differ only in which side is documented.
These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.
Source: ICD-10-CM tabular list (laterality variant derived from the code title)
Same condition, opposite side. T24.421D and T24.422D name the same condition on opposite sides of the body.
Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.
| T24.421DCorrosion of unspecified degree of right knee, subsequent encounter | T24.422DCorrosion of unspecified degree of left knee, 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 | Corrosion of unspecified degree of right knee, subsequent encounter is a billable ICD-10-CM diagnosis code (T24.421D). | Corrosion of unspecified degree of left knee, subsequent encounter is a billable ICD-10-CM diagnosis code (T24.422D). |
| 7th character | The appropriate 7th character is to be added to each code from category T24 | The appropriate 7th character is to be added to each code from category T24 |
| Includes | burns and corrosions of first degree [erythema] burns and corrosions of second degree [blisters][epidermal loss] burns and corrosions of third degree [deep necrosis of underlying tissue] [full- thickness skin loss] | burns and corrosions of first degree [erythema] burns and corrosions of second degree [blisters][epidermal loss] burns and corrosions of third degree [deep necrosis of underlying tissue] [full- thickness skin loss] |
| Use additional code | external cause code to identify place (Y92) code from category T31 or T32 to identify extent of body surface involved | external cause code to identify place (Y92) code from category T31 or T32 to identify extent of body surface involved |
| Code first | (T51-T65) to identify chemical and intent | (T51-T65) to identify chemical and intent |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources