2026 ICD-10-CM Diagnosis Code T80.52XAAnaphylactic reaction due to vaccination, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T80

ICD-10-CM T80.52XA
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T80.52XA is a billable ICD-10-CM diagnosis code for anaphylactic reaction due to vaccination, 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 915 through 916. 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
T80.52XA
Billable Status
Yes — Valid for Submission
Code Describes
Anaphylactic reaction due to vaccination, initial encounter
Short Description
Anaphylactic reaction due to vaccination, initial encounter
Same as the full description in the CMS dataset.
Parent Code
T80.52
Anaphylactic reaction due to vaccination

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT80Complications following infusion, transfusion and therapeutic injection
This CodeT80.52XAAnaphylactic reaction due to vaccination, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adverse reaction to component of vaccine product containing low dose acellular Bordetella pertussis and Clostridium tetani and low dose Corynebacterium diphtheriae antigens
  • Adverse reaction to component of vaccine product containing only acellular Bordetella pertussis and Clostridium tetani and Corynebacterium diphtheriae antigens
  • Adverse reaction to component of vaccine product containing only live attenuated Human alphaherpesvirus 3 antigen
  • Adverse reaction to component of Vaccine product containing Rotavirus antigen
  • Adverse reaction to Haemophilus influenzae type b vaccine
  • Adverse reaction to hepatitis A vaccine
  • Adverse reaction to hepatitis B vaccine
  • Adverse reaction to Human papillomavirus vaccine
  • Adverse reaction to influenza virus vaccine
  • Adverse reaction to measles vaccine
  • Adverse reaction to meningococcal vaccine
  • Adverse reaction to mumps vaccine
  • Adverse reaction to pertussis vaccine
  • Adverse reaction to pneumococcal vaccine
  • Adverse reaction to poliomyelitis vaccine
  • Adverse reaction to rubella vaccine
  • Adverse reaction to Varicella-zoster virus vaccine
  • Anaphylaxis caused by component of vaccine product
  • Anaphylaxis caused by component of vaccine product against severe acute respiratory syndrome coronavirus 2
  • Anaphylaxis caused by component of vaccine product containing low dose acellular Bordetella pertussis and Clostridium tetani and low dose Corynebacterium diphtheriae antigens
  • Anaphylaxis caused by component of vaccine product containing only acellular Bordetella pertussis and Clostridium tetani and Corynebacterium diphtheriae antigens
  • Anaphylaxis caused by rotavirus vaccine
  • Anaphylaxis caused by vaccine containing Human alphaherpesvirus 3 antigen
  • Anaphylaxis caused by vaccine product containing Hepatitis A virus antigen
  • Anaphylaxis caused by vaccine product containing Hepatitis B virus antigen
  • Anaphylaxis caused by vaccine product containing human alphaherpesvirus 3 recombinant surface glycoprotein E antigen
  • Anaphylaxis caused by vaccine product containing Human papillomavirus antigen
  • Anaphylaxis caused by vaccine product containing human poliovirus antigen
  • Anaphylaxis caused by vaccine product containing Influenza virus antigen
  • Anaphylaxis caused by vaccine product containing live attenuated human alphaherpesvirus 3 antigen
  • Anaphylaxis caused by vaccine product containing Measles morbillivirus and Mumps orthorubulavirus and Rubella virus antigens
  • Anaphylaxis caused by vaccine product containing only Clostridium tetani and Corynebacterium diphtheriae antigens
  • Anaphylaxis caused by vaccine product containing only Haemophilus influenzae type b antigen
  • Anaphylaxis caused by vaccine product containing only Neisseria meningitidis antigen
  • Anaphylaxis caused by vaccine product containing Streptococcus pneumoniae antigen

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Complications following infusion, transfusion and therapeutic injection (T80). 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.

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

Patient EducationClinical

Anaphylaxis

Anaphylaxis is a serious allergic reaction. It can begin very quickly, and symptoms may be life-threatening. The most common causes are reactions to foods (especially peanuts), medications, and stinging insects. Other causes include exercise and exposure to latex. Sometimes no cause can be found.

Read the full article at MedlinePlus

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

Convert T80.52XA to ICD-9-CMHistory

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

ICD-9-CM
999.42 Anaphyl react d/t vaccin
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T80.52XAOverview

Is T80.52XA (Anaphylactic reaction due to vaccination) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report anaphylactic reaction due to vaccination, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T80.52XA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for anaphylactic reaction due to vaccination, such as an emergency visit or first evaluation.

What MS-DRG does T80.52XA group to?

When anaphylactic reaction due to vaccination, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 915, 916, with relative weights from 0.6663 to 1.6816 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T80.52XA?

Under the General Equivalence Mappings, anaphylactic reaction due to vaccination, initial encounter converts to ICD-9-CM 999.42 (anaphyl react d/t vaccin). 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.