2026 ICD-10-CM Diagnosis Code T78Adverse effects, not elsewhere classified
T78 is a non-billable ICD-10-CM category code for adverse effects, not elsewhere classified, so it cannot be submitted on claims. Use a more specific code from this category instead, such as T78.00XA, T78.00XD, T78.00XS, and T78.01XA.
Code Identity
Code Classification
Specific Coding for Adverse effects, not elsewhere classifiedOverview
Non-specific codes like T78 require more characters. Use one of these billable codes instead:
T78.0 for Anaphylactic reaction due to food
T78.00 for Anaphylactic reaction due to unspecified food
T78.01 for Anaphylactic reaction due to peanuts
T78.02 for Anaphylactic reaction due to shellfish (crustaceans)
T78.03 for Anaphylactic reaction due to other fish
T78.04 for Anaphylactic reaction due to fruits and vegetables
T78.05 for Anaphylactic reaction due to tree nuts and seeds
T78.06 for Anaphylactic reaction due to food additives
T78.07 for Anaphylactic reaction due to milk and dairy products
T78.08 for Anaphylactic reaction due to eggs
T78.09 for Anaphylactic reaction due to other food products
T78.1 for Other adverse food reactions, not elsewhere classified
T78.11 for Other adverse food reactions due to milk and dairy products
T78.12 for Other adverse food reaction due to eggs
T78.19 for Other adverse food reactions, not elsewhere classified
T78.2 for Anaphylactic shock, unspecified
T78.3 for Angioneurotic edema
T78.4 for Other and unspecified allergy
T78.40 for Allergy, unspecified
T78.41 for Arthus phenomenon
T78.49 for Other allergy
T78.8 for Other adverse effects, not elsewhere classified
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.
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 2 Excludes
7th Character Note
- The appropriate 7th character is to be added to each code from category T78
7th Character
- A - initial encounter
- D - subsequent encounter
- S - sequela
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
Indicates that a seventh character is to be assigned to codes in a subcategory.
Code HistoryHistory
Questions About T78Overview
Is T78 (Adverse effects, not elsewhere classified) a billable code?
No. This is a category header that groups the codes for adverse effects, not elsewhere classified, and headers cannot be submitted on claims. Claims for adverse effects, not elsewhere classified need a more specific code from this category, such as T78.00XA, T78.00XD, and T78.00XS.
