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T23.329A vs T23.329D

T23.329A (Burn of third degree of unspecified single finger (nail) except thumb, initial encounter) compared with T23.329D (Burn of third degree of unspecified single finger (nail) except thumb, subsequent encounter), from the official CMS tabular data. T23.329A and T23.329D code the same injury at a different phase of treatment. MedCoder-derived

Can these codes be reported together?

Review

Encounter relationship

T23.329A
Initial encounter
Burn of third degree of unspecified single finger (nail) except thumb, initial encounter
↔
T23.329D
Subsequent encounter
Burn of third degree of unspecified single finger (nail) except thumb, subsequent encounter

What we found

Same injury, other encounter phase.T23.329A and T23.329D code the same injury at a different phase of treatment, set by the 7th character.

The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.

What to review

Use the 7th character that matches the encounter being coded (initial, subsequent or sequela); one encounter takes one of them.

Guide: 7th characters: initial, subsequent, sequelaCheck these on a claim

Why it matters

The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.

Source / rule

ICD-10-CM Official Guidelines, Section I.C.19.a

Side by side

T23.329ABurn of third degree of unspecified single finger (nail) except thumb, initial encounterT23.329DBurn of third degree of unspecified single finger (nail) except thumb, subsequent encounter
Billing statusBillableBillable
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)
DefinitionBurn of third degree of unspecified single finger (nail) except thumb, initial encounter is a billable ICD-10-CM diagnosis code (T23.329A).Burn of third degree of unspecified single finger (nail) except thumb, subsequent encounter is a billable ICD-10-CM diagnosis code (T23.329D).
7th characterThe appropriate 7th character is to be added to each code from category T23The 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 the source, place and intent of the burn (X00-X19, X75-X77, X96-X98, Y92)
code from category T31 or T32 to identify extent of body surface involved
external cause code to identify the source, place and intent of the burn (X00-X19, X75-X77, X96-X98, Y92)
code from category T31 or T32 to identify extent of body surface involved

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

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Derived from the official CMS ICD-10-CM tabular data (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources