2026 ICD-10-CM Diagnosis Code T81.61XAAseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter
T81.61XA is a billable ICD-10-CM diagnosis code for aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 919 through 921. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of other surgical or medical care, injury, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Aseptic peritoneal eosinophilia after dialysis
- Aseptic peritonitis
- Aseptic peritonitis following procedure
- Barium peritonitis
- Chemical peritonitis
- Chemical peritonitis due to and following a procedure
- Starch peritonitis
- Talc peritonitis
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Complications of procedures, not elsewhere classified (T81). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Chemical Peritonitis
a non-infectious inflammation of the peritoneum.
Patient EducationClinical
Peritoneal Disorders
Your peritoneum is the tissue that lines your abdominal wall and covers most of the organs in your abdomen. A liquid, peritoneal fluid, lubricates the surface of this tissue.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T81.61XA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T81.61XAOverview
Is T81.61XA a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T81.61XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for aseptic peritonitis due to foreign substance accidentally left during a procedure, such as an emergency visit or first evaluation.
What MS-DRG does T81.61XA group to?
When aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 919, 920, 921, with relative weights from 0.6884 to 1.8308 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of T81.61XA?
Under the General Equivalence Mappings, aseptic peritonitis due to foreign substance accidentally left during a procedure, initial encounter converts to ICD-9-CM 998.7 (postop forgn subst react). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
