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T33.40 vs T33.42

T33.40 (Superficial frostbite of unspecified arm) compared with T33.42 (Superficial frostbite of left arm), from the official CMS tabular data. T33.40 and T33.42 code the same condition on opposite sides. MedCoder-derived

Relationship

Review

Laterality relationship

T33.40
Unspecified
Superficial frostbite of unspecified arm
T33.42
Left
Superficial frostbite of left arm

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)

Can these codes be reported together?

Same condition, opposite side. T33.40 and T33.42 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.

Side by side

T33.40Superficial frostbite of unspecified armT33.42Superficial frostbite of left arm
Billing statusNon-billable header

Report instead: T33.40XA, T33.40XD, T33.40XS

Non-billable header

Report instead: T33.42XA, T33.42XD, T33.42XS

ClassificationS00-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)
DefinitionSuperficial frostbite of unspecified arm is a non-billable ICD-10-CM category code (T33.40).Superficial frostbite of left arm is a non-billable ICD-10-CM category code (T33.42).
7th characterThe appropriate 7th character is to be added to each code from category T33The appropriate 7th character is to be added to each code from category T33
Includes
frostbite with partial thickness skin loss
frostbite with partial thickness skin loss

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources