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T71.20XA vs T71.20XS

T71.20XA (Asphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, initial encounter) compared with T71.20XS (Asphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, sequela), from the official CMS tabular data. T71.20XA and T71.20XS code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

T71.20XA
Initial encounter
Asphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, initial encounter
T71.20XS
Sequela
Asphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, sequela

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. T71.20XA and T71.20XS 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

T71.20XAAsphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, initial encounterT71.20XSAsphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, sequela
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 systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, initial encounter is a billable ICD-10-CM diagnosis code (T71.20A).Asphyxiation due to systemic oxygen deficiency due to low oxygen content in ambient air due to unspecified cause, sequela is a billable ICD-10-CM diagnosis code (T71.20S).
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

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