T78.120S: Other adverse food reaction due to egg with tolerance to baked egg, sequela

New code · FY2026

Billable: use this code on claims.

• New code, effective October 1, 2025 (FY2026).

Code breakdown

Coding notes

Excludes1 (from T78.120)

• Other adverse food reaction due to egg with reactivity to baked egg (T78.121)

Excludes1 (from T78.1)

• anaphylactic reaction or shock due to adverse food reaction (T78.0-)
• anaphylactic reaction due to food (T78.0-)
• bacterial food borne intoxications (A05.-)

Excludes2 (from T78.1)

• allergic and dietetic gastroenteritis and colitis (K52.29)
• allergic rhinitis due to food (J30.5)
• dermatitis due to food in contact with skin (L23.6, L24.6, L25.4)
• dermatitis due to ingested food (L27.2)
• food protein-induced enterocolitis syndrome (K52.21)
• food protein-induced enteropathy (K52.22)

Use additional code (from T78.1)

• code to identify the type of reaction, if applicable

Excludes2 (from T78)

• complications of surgical and medical care NEC (T80-T88)

7th character (from T78)

• The appropriate 7th character is to be added to each code from category T78

7th characters (category T78)

• A initial encounter
• D subsequent encounter
• S sequela

Medicare coverage

T78.120S is listed as a covered diagnosis in 8 Medicare billing and coding articles:

• A56558 Billing and Coding: Allergy Testing
• A57068 Billing and Coding: Ocular Photography - External
• A57531 Billing and Coding: Allergy Testing
• A60361 Billing and Coding: Allergy Diagnostic Testing
• A60364 Billing and Coding: Allergy Diagnostic Testing
• A60375 Billing and Coding: Allergy Diagnostic Testing
• A60377 Billing and Coding: Allergy Diagnostic Testing
• A60391 Billing and Coding: Allergy Diagnostic Testing

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All FY2026 ICD-10-CM changes

ICD-10-CM codes and descriptions are from the CMS and NCHS code files. Coverage is from the CMS Medicare Coverage Database billing and coding articles.