T23.741A vs T23.742A

T23.741A (Corrosion of third degree of multiple right fingers (nail), including thumb, initial encounter) compared with T23.742A (Corrosion of third degree of multiple left fingers (nail), including thumb, initial encounter), from the official CMS tabular data. T23.741A and T23.742A code the same condition on opposite sides. MedCoder-derived

Relationship

Review

Laterality relationship

T23.741A

Right

Corrosion of third degree of multiple right fingers (nail), including thumb, initial encounter

↔

T23.742A

Left

Corrosion of third degree of multiple left fingers (nail), including thumb, initial encounter

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. T23.741A and T23.742A 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

	T23.741ACorrosion of third degree of multiple right fingers (nail), including thumb, initial encounter	T23.742ACorrosion of third degree of multiple left fingers (nail), including thumb, initial encounter
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	Corrosion of third degree of multiple right fingers (nail), including thumb, initial encounter is a billable ICD-10-CM diagnosis code (T23.741A).	Corrosion of third degree of multiple left fingers (nail), including thumb, initial encounter is a billable ICD-10-CM diagnosis code (T23.742A).
7th character	The appropriate 7th character is to be added to each code from category T23	The appropriate 7th character is to be added to each code from category T23
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

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