2027 ICD-10-CM Diagnosis Code T81.42XAInfection following a procedure, deep incisional surgical site, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T81

ICD-10-CM T81.42XA
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T81.42XA is a billable ICD-10-CM diagnosis code for infection following a procedure, deep incisional 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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793, 856 through 858, 862 through 863. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 55 closely related codes. Coders also document this condition as deep incisional surgical site infection. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of other surgical or medical care, injury, initial encounter.

Code Identity

ICD-10-CM Code
T81.42XA
Billable Status
Yes — Valid for Submission
Code Describes
Infection following a procedure, deep incisional surgical site, initial encounter
Short Description
Infct fol a procedure, deep incisional surgical site, init
Parent Code
T81.42
Infection following a procedure, deep incisional surgical site

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT81Complications of procedures, not elsewhere classified
This CodeT81.42XAInfection following a procedure, deep incisional surgical site, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Deep incisional surgical site infection
  • Postoperative wound infection
  • Postoperative wound infection-deep

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 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T81.42XA: its own notes plus those printed at T81.4, T81, block T80-T88, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From T81.4 Infection following a procedure applies to 18 codes
  • bleb associated endophthalmitis (H59.4-)
  • infection due to infusion, transfusion and therapeutic injection (T80.2-)
  • infection due to prosthetic devices, implants and grafts (T82.6-T82.7, T83.5-T83.6, T84.5-T84.7, T85.7)
  • obstetric surgical wound infection (O86.0-)
  • postprocedural fever NOS (R50.82)
  • postprocedural retroperitoneal abscess (K68.11)
From T81 Complications of procedures, not elsewhere classified applies to 240 codes
From Block T80-T88 Complications of surgical and medical care, not elsewhere classified applies to 1,683 codes
  • any encounters with medical care for postprocedural conditions in which no complications are present, such as:
  • artificial opening status (Z93.-)
  • closure of external stoma (Z43.-)
  • fitting and adjustment of external prosthetic device (Z44.-)
  • burns and corrosions from local applications and irradiation (T20-T32)
  • complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
  • mechanical complication of respirator [ventilator] (J95.850)
  • poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
  • postprocedural fever (R50.82)
  • specified complications classified elsewhere, such as:
  • cerebrospinal fluid leak from spinal puncture (G97.0)
  • colostomy malfunction (K94.0-)
  • disorders of fluid and electrolyte imbalance (E86-E87)
  • functional disturbances following cardiac surgery (I97.0-I97.1)
  • intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
  • ostomy complications (J95.0-, K94.-, N99.5-)
  • postgastric surgery syndromes (K91.1)
  • postlaminectomy syndrome NEC (M96.1)
  • postmastectomy lymphedema syndrome (I97.2)
  • postsurgical blind-loop syndrome (K91.2)
  • ventilator associated pneumonia (J95.851)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From T81.4 Infection following a procedure applies to 18 codes
  • code to identify infection
  • code (R65.2-) to identify severe sepsis, if applicable
From T81 Complications of procedures, not elsewhere classified applies to 240 codes
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
From Block T80-T88 Complications of surgical and medical care, not elsewhere classified applies to 1,683 codes
  • 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)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From T81.4 Infection following a procedure applies to 18 codes
  • if applicable, disruption of internal operation (surgical) wound (T81.32-)

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From T81 Complications of procedures, not elsewhere classified applies to 240 codes
  • The appropriate 7th character is to be added to each code from category T81
Values for category T81 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name T81.42XA, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming T81.42XA: they are not reported together with it, unless the two conditions are unrelated.

  • O86.0 Infection of obstetric surgical wound
    complications of procedures, not elsewhere classified (T81.4-) names T81.4-, which includes this code
  • R50.82 Postprocedural fever
    postprocedural infection (T81.4-) names T81.4-, which includes this code

Excludes2 3

These codes carry an Excludes2 note naming T81.42XA: its condition is not part of those codes, and both may be reported when the patient has both.

  • K68.11 Postprocedural retroperitoneal abscess
    infection following procedure (T81.4-) names T81.4-, which includes this code
  • T80.2 Infections following infusion, transfusion and therapeutic injection
    postprocedural infections (T81.4-) names T81.4-, which includes this code
  • T88 Other complications of surgical and medical care, not elsewhere classified
    complication following procedure NEC (T81.-) names T81.-, which includes this code

Code First 2

These codes say to code first a condition named in the note, and T81.42XA is one of the conditions named.

  • J98.51 Mediastinitis
    underlying condition, if applicable, such as postoperative mediastinitis (T81.-) names T81.-, which includes this code
  • R65.2 Severe sepsis
    infection following a procedure (T81.4-) names T81.4-, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ037
Complication of other surgical or medical care, injury, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

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 T81.42XA replaces the following previously assigned code(s):

  • T81.4XXA - Infection following a procedure, initial encounter
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T81.42XAOverview

Is T81.42XA a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report infection following a procedure, deep incisional surgical site, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in T81.42XA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for infection following a procedure, deep incisional surgical site, such as an emergency visit or first evaluation.

What MS-DRG does T81.42XA group to?

When infection following a procedure, deep incisional surgical site, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 858, 856, 857, 863, 862, with relative weights from 0.9868 to 4.4822 depending on complications. Higher weights mean higher Medicare reimbursement.

Is T81.42XA a CC or MCC?

CMS lists T81.42XA as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 55 closely related codes in its exclusion list.

Does T81.42XA need an additional code?

When the condition applies, yes. The Use Additional Code note at T81.4, which applies to T81.42XA, reads: code to identify infection; code (R65.2-) to identify severe sepsis, if applicable. The additional code is reported after T81.42XA.