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T17.900A vs T17.900S

T17.900A (Unspecified foreign body in respiratory tract, part unspecified causing asphyxiation, initial encounter) compared with T17.900S (Unspecified foreign body in respiratory tract, part unspecified causing asphyxiation, sequela), from the official CMS tabular data. T17.900A and T17.900S code the same injury at a different phase of treatment. MedCoder-derived

Relationship

Review

Encounter relationship

T17.900A
Initial encounter
Unspecified foreign body in respiratory tract, part unspecified causing asphyxiation, initial encounter
↔
T17.900S
Sequela
Unspecified foreign body in respiratory tract, part unspecified causing asphyxiation, 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. T17.900A and T17.900S 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

T17.900AUnspecified foreign body in respiratory tract, part unspecified causing asphyxiation, initial encounterT17.900SUnspecified foreign body in respiratory tract, part unspecified causing asphyxiation, sequela
Billing statusBillableBillable
ClassificationS00-T88 — Injury, poisoning and certain other consequences of external causesS00-T88 — Injury, poisoning and certain other consequences of external causes
DefinitionUnspecified foreign body in respiratory tract, part unspecified causing asphyxiation, initial encounter is a billable ICD-10-CM diagnosis code (T17.900A).Unspecified foreign body in respiratory tract, part unspecified causing asphyxiation, sequela is a billable ICD-10-CM diagnosis code (T17.900S).
7th characterThe appropriate 7th character is to be added to each code from category T17The appropriate 7th character is to be added to each code from category T17
Use additional code
code, if known, for foreign body entering into or through a natural orifice (W44.-)
code, if known, for foreign body entering into or through a natural orifice (W44.-)
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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