2026 ICD-10-CM Diagnosis Code T81.43XAInfection following a procedure, organ and space surgical site, initial encounter
T81.43XA is a billable ICD-10-CM diagnosis code for infection following a procedure, organ and space surgical site, 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 856 through 858, 862 through 863. Coders also document this condition as abscess of peritoneum. 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.
- Abscess of peritoneum
- Intra-abdominal infection following surgical procedure
- Organ-space surgical site infection
- Postoperative intra-abdominal abscess
- Postoperative subphrenic abscess
- Postoperative wound infection
- Postoperative wound infection-deep
- Postprocedural intraabdominal abscess
- Subdiaphragmatic abscess
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.
Patient EducationClinical
After Surgery
After any operation, you'll have some side effects. There is usually some pain with surgery. There may also be swelling and soreness around the area that the surgeon cut. Your surgeon can tell you which side effects to expect.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code History & ChangesHistory
Replacement T81.43XA replaces the following previously assigned code(s):
- T81.4XXA - Infection following a procedure, initial encounter
Questions About T81.43XAOverview
Is T81.43XA a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report infection following a procedure, organ and space surgical site, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T81.43XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for infection following a procedure, organ and space surgical site, such as an emergency visit or first evaluation.
What MS-DRG does T81.43XA group to?
When infection following a procedure, organ and space surgical site, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 856, 857, 858, 862, 863, with relative weights from 0.9979 to 4.5487 depending on complications. Higher weights mean higher Medicare reimbursement.
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.
