ICD-10-CM · FY 2026 APRIL UPDATE
T78.4
Other and unspecified allergy
Diagnosis reference
Nonbillable categoryThis entry is a category or subcategory. Choose the appropriate billable descendant based on the clinical documentation.
Effective periodOctober 1, 2026–September 30, 2027
SourceCMS ICD-10-CM order file
ClassificationDiagnosis · clinical modification
Related entries
Up to 30 descendants in this category
| CODE | DESCRIPTION | TYPE |
|---|---|---|
| T78.40 | Allergy, unspecified | Category |
| T78.40XA | Allergy, unspecified, initial encounter | Billable |
| T78.40XD | Allergy, unspecified, subsequent encounter | Billable |
| T78.40XS | Allergy, unspecified, sequela | Billable |
| T78.41 | Arthus phenomenon | Category |
| T78.41XA | Arthus phenomenon, initial encounter | Billable |
| T78.41XD | Arthus phenomenon, subsequent encounter | Billable |
| T78.41XS | Arthus phenomenon, sequela | Billable |
| T78.49 | Other allergy | Category |
| T78.49XA | Other allergy, initial encounter | Billable |
| T78.49XD | Other allergy, subsequent encounter | Billable |
| T78.49XS | Other allergy, sequela | Billable |
Use the complete reference
This reference does not reproduce the full tabular hierarchy, inclusion notes, Excludes1/2 notes, sequencing instructions, or seventh-character rules. Review the official tables and coding guidelines.
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