L55 vs T66
L55 (Sunburn) compared with T66 (Radiation sickness, unspecified), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. T66 carries an Excludes1 note covering L55: “radiation related disorders of the skin and subcutaneous tissue (L55-L59)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
No — do not report together. T66 carries an Excludes1 note covering L55: “sunburn (L55.-)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| L55Sunburn | T66Radiation sickness, unspecified | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | L00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Sunburn is a non-billable ICD-10-CM category code (L55). | Radiation sickness, unspecified is a non-billable ICD-10-CM category code (T66). |
| 7th character | — | The appropriate 7th character is to be added to code T66 |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources