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T71.29XA vs T71.29XD

T71.29XA (Asphyxiation due to being trapped in other low oxygen environment, initial encounter) compared with T71.29XD (Asphyxiation due to being trapped in other low oxygen environment, subsequent encounter), from the official CMS tabular data. T71.29XA and T71.29XD code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

T71.29XA
Initial encounter
Asphyxiation due to being trapped in other low oxygen environment, initial encounter
↔
T71.29XD
Subsequent encounter
Asphyxiation due to being trapped in other low oxygen environment, subsequent encounter

Same underlying diagnosis, different encounter phase.

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

Can these codes be reported together?

Same injury, other encounter phase. T71.29XA and T71.29XD 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.

Side by side

T71.29XAAsphyxiation due to being trapped in other low oxygen environment, initial encounterT71.29XDAsphyxiation due to being trapped in other low oxygen environment, 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)
DefinitionAsphyxiation due to being trapped in other low oxygen environment, initial encounter is a billable ICD-10-CM diagnosis code (T71.29A).Asphyxiation due to being trapped in other low oxygen environment, subsequent encounter is a billable ICD-10-CM diagnosis code (T71.29D).
7th characterThe appropriate 7th character is to be added to each code from category T71The appropriate 7th character is to be added to each code from category T71
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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