Adverse effects, not elsewhere classified (T78) ICD-10-CM
The T78 code range covers adverse effects, not elsewhere classified with 116 ICD-10-CM diagnosis codes. 81 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 2 Excludes
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.
7th Character Note
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.
- The appropriate 7th character is to be added to each code from category T78
7th Character
Indicates that a seventh character is to be assigned to codes in a subcategory.
- A - initial encounter
- D - subsequent encounter
- S - sequela
Codes in the T78 Range 116 codes · 81 billable
- T78 Adverse effects, not elsewhere classifiedNon-billable
- T78.0 Anaphylactic reaction due to foodNon-billable
- T78.00 Anaphylactic reaction due to unspecified foodNon-billable
- T78.00XA Anaphylactic reaction due to unspecified food, initial encounter
- T78.00XD Anaphylactic reaction due to unspecified food, subsequent encounter
- T78.00XS Anaphylactic reaction due to unspecified food, sequela
- T78.01 Anaphylactic reaction due to peanutsNon-billable
- T78.01XA Anaphylactic reaction due to peanuts, initial encounter
- T78.01XD Anaphylactic reaction due to peanuts, subsequent encounter
- T78.01XS Anaphylactic reaction due to peanuts, sequela
- T78.02 Anaphylactic reaction due to shellfish (crustaceans)Non-billable
- T78.02XA Anaphylactic reaction due to shellfish (crustaceans), initial encounter
- T78.02XD Anaphylactic reaction due to shellfish (crustaceans), subsequent encounter
- T78.02XS Anaphylactic reaction due to shellfish (crustaceans), sequela
- T78.03 Anaphylactic reaction due to other fishNon-billable
- T78.03XA Anaphylactic reaction due to other fish, initial encounter
- T78.03XD Anaphylactic reaction due to other fish, subsequent encounter
- T78.03XS Anaphylactic reaction due to other fish, sequela
- T78.04 Anaphylactic reaction due to fruits and vegetablesNon-billable
- T78.04XA Anaphylactic reaction due to fruits and vegetables, initial encounter
- T78.04XD Anaphylactic reaction due to fruits and vegetables, subsequent encounter
- T78.04XS Anaphylactic reaction due to fruits and vegetables, sequela
- T78.05 Anaphylactic reaction due to tree nuts and seedsNon-billable
- T78.05XA Anaphylactic reaction due to tree nuts and seeds, initial encounter
- T78.05XD Anaphylactic reaction due to tree nuts and seeds, subsequent encounter
- T78.05XS Anaphylactic reaction due to tree nuts and seeds, sequela
- T78.06 Anaphylactic reaction due to food additivesNon-billable
- T78.06XA Anaphylactic reaction due to food additives, initial encounter
- T78.06XD Anaphylactic reaction due to food additives, subsequent encounter
- T78.06XS Anaphylactic reaction due to food additives, sequela
- T78.07 Anaphylactic reaction due to milk and dairy productsNon-billable
- T78.070 Anaphylactic reaction due to milk and dairy products with tolerance to baked milkNon-billable
- T78.070A Anaphylactic reaction due to milk and dairy products with tolerance to baked milk, initial encounter
- T78.070D Anaphylactic reaction due to milk and dairy products with tolerance to baked milk, subsequent encounter
- T78.070S Anaphylactic reaction due to milk and dairy products with tolerance to baked milk, sequela
- T78.071 Anaphylactic reaction due to milk and dairy products with reactivity to baked milkNon-billable
- T78.071A Anaphylactic reaction due to milk and dairy products with reactivity to baked milk, initial encounter
- T78.071D Anaphylactic reaction due to milk and dairy products with reactivity to baked milk, subsequent encounter
- T78.071S Anaphylactic reaction due to milk and dairy products with reactivity to baked milk, sequela
- T78.079 Anaphylactic reaction due to milk and dairy products, unspecifiedNon-billable
- T78.079A Anaphylactic reaction due to milk and dairy products, unspecified, initial encounter
- T78.079D Anaphylactic reaction due to milk and dairy products, unspecified, subsequent encounter
- T78.079S Anaphylactic reaction due to milk and dairy products, unspecified, sequela
- T78.08 Anaphylactic reaction due to eggsNon-billable
- T78.080 Anaphylactic reaction due to egg with tolerance to baked eggNon-billable
- T78.080A Anaphylactic reaction due to egg with tolerance to baked egg, initial encounter
- T78.080D Anaphylactic reaction due to egg with tolerance to baked egg, subsequent encounter
- T78.080S Anaphylactic reaction due to egg with tolerance to baked egg, sequela
- T78.081 Anaphylactic reaction due to egg with reactivity to baked eggNon-billable
- T78.081A Anaphylactic reaction due to egg with reactivity to baked egg, initial encounter
- T78.081D Anaphylactic reaction due to egg with reactivity to baked egg, subsequent encounter
- T78.081S Anaphylactic reaction due to egg with reactivity to baked egg, sequela
- T78.089 Anaphylactic reaction due to eggs, unspecifiedNon-billable
- T78.089A Anaphylactic reaction due to eggs, unspecified, initial encounter
- T78.089D Anaphylactic reaction due to eggs, unspecified, subsequent encounter
- T78.089S Anaphylactic reaction due to eggs, unspecified, sequela
- T78.09 Anaphylactic reaction due to other food productsNon-billable
- T78.09XA Anaphylactic reaction due to other food products, initial encounter
- T78.09XD Anaphylactic reaction due to other food products, subsequent encounter
- T78.09XS Anaphylactic reaction due to other food products, sequela
- T78.1 Other adverse food reactions, not elsewhere classifiedNon-billable
- T78.11 Other adverse food reactions due to milk and dairy productsNon-billable
- T78.110 Other adverse food reactions due to milk and dairy products with tolerance to baked milkNon-billable
- T78.110A Other adverse food reactions due to milk and dairy products with tolerance to baked milk, initial encounter
- T78.110D Other adverse food reactions due to milk and dairy products with tolerance to baked milk, subsequent encounter
- T78.110S Other adverse food reactions due to milk and dairy products with tolerance to baked milk, sequela
- T78.111 Other adverse food reaction due to milk and dairy products with reactivity to baked milkNon-billable
- T78.111A Other adverse food reaction due to milk and dairy products with reactivity to baked milk, initial encounter
- T78.111D Other adverse food reaction due to milk and dairy products with reactivity to baked milk, subsequent encounter
- T78.111S Other adverse food reaction due to milk and dairy products with reactivity to baked milk, sequela
- T78.119 Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecifiedNon-billable
- T78.119A Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecified, initial encounter
- T78.119D Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecified, subsequent encounter
- T78.119S Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecified, sequela
- T78.12 Other adverse food reaction due to eggsNon-billable
- T78.120 Other adverse food reaction due to egg with tolerance to baked eggNon-billable
- T78.120A Other adverse food reaction due to egg with tolerance to baked egg, initial encounter
- T78.120D Other adverse food reaction due to egg with tolerance to baked egg, subsequent encounter
- T78.120S Other adverse food reaction due to egg with tolerance to baked egg, sequela
- T78.121 Other adverse food reaction due to egg with reactivity to baked eggNon-billable
- T78.121A Other adverse food reaction due to egg with reactivity to baked egg, initial encounter
- T78.121D Other adverse food reaction due to egg with reactivity to baked egg, subsequent encounter
- T78.121S Other adverse food reaction due to egg with reactivity to baked egg, sequela
- T78.129 Other adverse food reaction due to egg with baked egg tolerance/reactivity, unspecifiedNon-billable
- T78.129A Other adverse food reaction due to egg with baked egg tolerance/reactivity, unspecified, initial encounter
- T78.129D Other adverse food reaction due to egg with baked egg tolerance/reactivity, unspecified, subsequent encounter
- T78.129S Other adverse food reaction due to egg with baked egg tolerance/reactivity, unspecified, sequela
- T78.19 Other adverse food reactions, not elsewhere classifiedNon-billable
- T78.19XA Other adverse food reactions, not elsewhere classified, initial encounter
- T78.19XD Other adverse food reactions, not elsewhere classified, subsequent encounter
- T78.19XS Other adverse food reactions, not elsewhere classified, sequela
- T78.2 Anaphylactic shock, unspecifiedNon-billable
- T78.2XXA Anaphylactic shock, unspecified, initial encounter
- T78.2XXD Anaphylactic shock, unspecified, subsequent encounter
- T78.2XXS Anaphylactic shock, unspecified, sequela
- T78.3 Angioneurotic edemaNon-billable
- T78.3XXA Angioneurotic edema, initial encounter
- T78.3XXD Angioneurotic edema, subsequent encounter
- T78.3XXS Angioneurotic edema, sequela
- T78.4 Other and unspecified allergyNon-billable
- T78.40 Allergy, unspecifiedNon-billable
- T78.40XA Allergy, unspecified, initial encounter
- T78.40XD Allergy, unspecified, subsequent encounter
- T78.40XS Allergy, unspecified, sequela
- T78.41 Arthus phenomenonNon-billable
- T78.41XA Arthus phenomenon, initial encounter
- T78.41XD Arthus phenomenon, subsequent encounter
- T78.41XS Arthus phenomenon, sequela
- T78.49 Other allergyNon-billable
- T78.49XA Other allergy, initial encounter
- T78.49XD Other allergy, subsequent encounter
- T78.49XS Other allergy, sequela
- T78.8 Other adverse effects, not elsewhere classifiedNon-billable
- T78.8XXA Other adverse effects, not elsewhere classified, initial encounter
- T78.8XXD Other adverse effects, not elsewhere classified, subsequent encounter
- T78.8XXS Other adverse effects, not elsewhere classified, sequela
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the T78 range.
Anaphylactic Shock
Progression of anaphylaxis into systemic shock, which is characterized by significant reduction in tissue perfusion which leads to hypoxia and hypotension, and can lead to death if untreated.
Angioedema
Swelling involving the deep DERMIS, subcutaneous, or submucosal tissues, representing localized EDEMA. Angioedema often occurs in the face, lips, tongue, and larynx.
Arthus Reaction
A dermal inflammatory reaction produced under conditions of antibody excess, when a second injection of antigen produces intravascular antigen-antibody complexes which bind complement, causing cell clumping, endothelial damage, and vascular necrosis.
Hypersensitivity
Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.
About the T78 Code Range
This category brings together adverse food reactions, allergies, angioneurotic edema (swelling), and other adverse effects not elsewhere classified.
T78.0 identifies anaphylactic reactions to food, with subdivisions for specific foods and unspecified food. T78.1 separates other adverse food reactions by milk and dairy products, eggs, or other foods. Separate branches identify unspecified anaphylactic shock (T78.2), angioneurotic edema (T78.3), allergies (T78.4), and other adverse effects (T78.8).
A seventh character distinguishes an initial encounter, a subsequent encounter, or a sequela, meaning a later effect.
Questions About This Page
How many billable codes are in the T78 range?
Of the 116 codes in this range, 81 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the T78 range classify?
The range classifies adverse effects, not elsewhere classified. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
