T81.61XA vs T81.61XS

T81.61XA (Aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter) compared with T81.61XS (Aseptic peritonitis due to foreign substance accidentally left during a procedure, sequela), from the official CMS tabular data. T81.61XA and T81.61XS code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

T81.61XA

Initial encounter

Aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter

↔

T81.61XS

Sequela

Aseptic peritonitis due to foreign substance accidentally left during a procedure, 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. T81.61XA and T81.61XS 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

	T81.61XAAseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter	T81.61XSAseptic peritonitis due to foreign substance accidentally left during a procedure, sequela
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	Aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter is a billable ICD-10-CM diagnosis code (T81.61A).	Aseptic peritonitis due to foreign substance accidentally left during a procedure, sequela is a billable ICD-10-CM diagnosis code (T81.61S).
7th character	The appropriate 7th character is to be added to each code from category T81	The appropriate 7th character is to be added to each code from category T81
Includes	Chemical peritonitis	Chemical peritonitis
Use additional code	code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5) code(s) to identify the specified condition resulting from the complication code to identify devices involved and details of circumstances (Y62-Y82)	code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5) code(s) to identify the specified condition resulting from the complication code to identify devices involved and details of circumstances (Y62-Y82)

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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