T78.110A vs T78.110D

T78.110A (Other adverse food reactions due to milk and dairy products with tolerance to baked milk, initial encounter) compared with T78.110D (Other adverse food reactions due to milk and dairy products with tolerance to baked milk, subsequent encounter), from the official CMS tabular data. T78.110A and T78.110D code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

T78.110A

Initial encounter

Other adverse food reactions due to milk and dairy products with tolerance to baked milk, initial encounter

↔

T78.110D

Subsequent encounter

Other adverse food reactions due to milk and dairy products with tolerance to baked milk, subsequent encounter

Same underlying diagnosis, different encounter phase.

The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.

Source: ICD-10-CM Official Guidelines, Section I.C.19.a

Can these codes be reported together?

Same injury, other encounter phase. T78.110A and T78.110D code the same injury at a different phase of treatment, set by the 7th character.

The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.

Side by side

	T78.110AOther adverse food reactions due to milk and dairy products with tolerance to baked milk, initial encounter	T78.110DOther adverse food reactions due to milk and dairy products with tolerance to baked milk, subsequent encounter
Billing status	Billable	Billable
Classification	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
Definition	Other adverse food reactions due to milk and dairy products with tolerance to baked milk, initial encounter is a billable ICD-10-CM diagnosis code (T78.110A).	Other adverse food reactions due to milk and dairy products with tolerance to baked milk, subsequent encounter is a billable ICD-10-CM diagnosis code (T78.110D).
7th character	The appropriate 7th character is to be added to each code from category T78	The appropriate 7th character is to be added to each code from category T78
Use additional code	code to identify the type of reaction, if applicable	code to identify the type of reaction, if applicable

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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources