Billable / Specific Code
ICD-10-CM T78.121 is the diagnosis code for Other adverse food reaction due to egg with reactivity to baked egg. This code falls under the section "Other and unspecified effects of external causes" within Chapter 19 — Injury, poisoning and certain other consequences of external causes (S00-T88). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as T78.121. They are mutually exclusive:
Understanding where T78.121 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, T78.121 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
T78.121 is the ICD-10-CM diagnosis code for "Other adverse food reaction due to egg with reactivity to baked egg". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of T78.121 is T78.12 ("Other adverse food reaction due to eggs"). T78.121 provides a more specific classification within this category.
T78.121 is located in Section T66-T78 — "Other and unspecified effects of external causes" within Chapter 19 of the ICD-10-CM Tabular List.
Use T78.121 when the patients documented diagnosis matches "Other adverse food reaction due to egg with reactivity to baked egg" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Other adverse food reaction due to egg with reactivity to baked egg is T78.121.
Yes, T78.121 can be used as a primary diagnosis code since it is billable and specific.
T78.121 is in Chapter 19 of the ICD-10-CM Tabular List.
Type 1 Excludes for T78.121 include: Other adverse food reaction due to egg with tolerance to baked egg (T78.120).
Yes, T78.121 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.