2027 ICD-10-CM Diagnosis Code T88.0XXAInfection following immunization, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T88

ICD-10-CM T88.0XXA
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T88.0XXA is a billable ICD-10-CM diagnosis code for infection following immunization, 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, 867 through 869. 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 9 closely related codes. Coders also document this condition as COVID-19. 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
T88.0XXA
Billable Status
Yes — Valid for Submission
Code Describes
Infection following immunization, initial encounter
Short Description
Infection following immunization, initial encounter
Same as the full description in the CMS dataset.
Parent Code
T88.0
Infection following immunization

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT88Other complications of surgical and medical care, not elsewhere classified
This CodeT88.0XXAInfection following immunization, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • COVID-19
  • Infection following immunization
  • Primary immunodeficiency with post-measles-mumps-rubella vaccine viral infection
  • SARS-CoV-2 breakthrough infection
  • Sepsis following infusion, injection, transfusion AND/OR vaccination

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Other complications of surgical and medical care, not elsewhere classified (T88). 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 T88.0XXA: its own notes plus those printed at T88, 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 T88 Other complications of surgical and medical care, not elsewhere classified applies to 39 codes
  • complication following infusion, transfusion and therapeutic injection (T80.-)
  • complication following procedure NEC (T81.-)
  • complications of anesthesia in labor and delivery (O74.-)
  • complications of anesthesia in pregnancy (O29.-)
  • complications of anesthesia in puerperium (O89.-)
  • complications of devices, implants and grafts (T82-T85)
  • complications of obstetric surgery and procedure (O75.4)
  • dermatitis due to drugs and medicaments (L23.3, L24.4, L25.1, L27.0-L27.1)
  • poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4)
  • specified complications classified elsewhere
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 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.-)

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 T88 Other complications of surgical and medical care, not elsewhere classified applies to 39 codes
  • The appropriate 7th character is to be added to each code from category T88
Values for category T88 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 T88.0XXA, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming T88.0XXA: its condition is not part of those codes, and both may be reported when the patient has both.

  • T81 Complications of procedures, not elsewhere classified
    complications following immunization (T88.0-T88.1) names T88.0-T88.1, which includes this code

Code First 2

These codes say to code first a condition named in the note, and T88.0XXA is one of the conditions named.

  • A40 Streptococcal sepsis
    streptococcal sepsis following immunization (T88.0-) names T88.0-, which includes this code
  • A41 Other sepsis
    sepsis following immunization (T88.0-) names T88.0-, 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

Vaccines

Vaccines are injections (shots), liquids, pills, or nasal sprays that you take to teach your body's immune system to recognize and defend against harmful germs. For example, there are vaccines to protect against diseases caused by:

The full article covers:

  • What are vaccines?
  • What are the types of vaccines?
  • What happens in an immune response?
  • What are immunization and vaccination?
  • Why are vaccines important?
  • What is community immunity?
  • Are vaccines safe?
  • What is a vaccine schedule?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert T88.0XXA to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
999.39 Infect fol infus/inj/vac
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T88.0XXAOverview

What is the ICD-10 code for infection following immunization, initial encounter?

The ICD-10-CM code for infection following immunization, initial encounter is T88.0XXA (sometimes written as T880XXA). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is T88.0XXA (Infection following immunization) a billable code?

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

What does the 7th character A in T88.0XXA mean?

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

What MS-DRG does T88.0XXA group to?

When infection following immunization, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 858, 856, 857, 867, 869, 868, with relative weights from 0.6784 to 4.4822 depending on complications. Higher weights mean higher Medicare reimbursement.

Is T88.0XXA a CC or MCC?

CMS lists T88.0XXA 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 9 closely related codes in its exclusion list.