Non-Billable / Non-Specific Code
ICD-10-CM T78.4 is the diagnosis code for Other and unspecified allergy. 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 non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. 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 T78.4. They are mutually exclusive:
Understanding where T78.4 sits in the ICD-10-CM classification helps ensure proper coding:
No, T78.4 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
T78.4 is the ICD-10-CM diagnosis code for "Other and unspecified allergy". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of T78.4 is T78 ("Adverse effects, not elsewhere classified"). T78.4 provides a more specific classification within this category.
T78.4 is located in Section T66-T78 — "Other and unspecified effects of external causes" within Chapter 19 of the ICD-10-CM Tabular List.
T78.4 has 1918 sub-code(s) that provide more specific detail: A00, A01, A02, A03, A04 and more.
Use T78.4 when the patients documented diagnosis matches "Other and unspecified allergy" 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 and unspecified allergy is T78.4.
No, T78.4 is non-billable. Use a more specific sub-code for primary diagnosis billing.
T78.4 is in Chapter 19 of the ICD-10-CM Tabular List.
Type 1 Excludes for T78.4 include: specified types of allergic reaction such as:; allergic diarrhea (K52.29); allergic gastroenteritis and colitis (K52.29) and more.
Yes, T78.4 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.