Question 1

Is T78.121 a billable ICD-10 code?

Accepted Answer

Yes, T78.121 is a valid billable ICD-10-CM code for other adverse food reaction due to egg with reactivity to baked egg. It can be used for medical billing and reimbursement purposes.

Question 2

What does ICD-10 code T78.121 mean?

Accepted Answer

ICD-10-CM code T78.121 represents Other adverse food reaction due to egg with reactivity to baked egg. This code is part of the International Classification of Diseases, 10th Revision, Clinical Modification used for medical coding and billing in the United States.

Question 3

When was ICD-10 code T78.121 introduced?

Accepted Answer

Code T78.121 was added to ICD-10-CM in fiscal year 2026. ICD-10-CM codes are updated annually by the Centers for Medicare & Medicaid Services (CMS) to reflect advances in medical knowledge and clinical practice.

Question 4

What is the parent category for ICD-10 code T78.121?

Accepted Answer

The parent category for T78.121 is T78.12 (Other adverse food reaction due to eggs). This hierarchical classification helps organize related diagnoses for more accurate coding.

Question 5

What conditions are excluded from T78.121?

Accepted Answer

Code T78.121 has Type 1 Excludes (mutually exclusive conditions) including: Other adverse food reaction due to egg with tolerance to baked egg (T78.120). These conditions cannot be coded together with T78.121 as they represent different diagnoses.

Question 6

Does T78.121 require a 7th character extension?

Accepted Answer

Yes, T78.121 requires a 7th character to specify the encounter type. Available extensions include: A (initial encounter), D (subsequent encounter), S (sequela). Use "X" as a placeholder to fill empty positions before the 7th character (e.g., T78.121XXA for initial encounter). The extension indicates whether this is an initial visit, follow-up, or treatment for a late effect.

T78.121D2026

Excludes14Not coded together

Excludes29Not included here

Use Additional Code2Add code for detail

Notes2Additional information

Also Known As1Alternative terms

7th Character Extensions3Encounter type specifiers

Excluded By1Codes that exclude this one