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L55 vs T66.XXXD

L55 (Sunburn) compared with T66.XXXD (Radiation sickness, unspecified, subsequent encounter), 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.XXXD 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.XXXD 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

L55SunburnT66.XXXDRadiation sickness, unspecified, subsequent encounter
Billing statusNon-billable header

Report instead: L55.0, L55.1, L55.2, L55.9

Billable
ClassificationL00-L99 — Diseases of the Skin and Subcutaneous Tissue (L00-L99)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionSunburn is a non-billable ICD-10-CM category code (L55).Radiation sickness, unspecified, subsequent encounter is a billable ICD-10-CM diagnosis code (T66D).
7th characterThe 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