2026 ICD-10-CM Diagnosis Code T78.089AAnaphylactic reaction due to eggs, unspecified, initial encounter
T78.089A is a billable ICD-10-CM diagnosis code for anaphylactic reaction due to eggs, unspecified, 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. Coders also document this condition as anaphylaxis caused by egg.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Anaphylaxis caused by egg
- Egg white-induced anaphylaxis
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Adverse effects, not elsewhere classified (T78). 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.
Code History & ChangesHistory
New Code T78.089A was added to the ICD-10-CM code set for FY 2026, effective October 1, 2025.
Replacement T78.089A replaces the following previously assigned code(s):
- T78.08XA - Anaphylactic reaction due to eggs, initial encounter
Questions About T78.089AOverview
Is T78.089A (Anaphylactic reaction due to eggs, unspecified) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report anaphylactic reaction due to eggs, unspecified, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T78.089A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for anaphylactic reaction due to eggs, unspecified, such as an emergency visit or first evaluation.
What MS-DRG does T78.089A group to?
When anaphylactic reaction due to eggs, unspecified, 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.
