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T78.49XD

T78.49XD: Other allergy, subsequent encounter

Billable / specific codeICD-10-CMPOA exempt

T78.49XD is a billable, specific ICD-10-CM code for other allergy, subsequent encounter. It is valid for submission on a claim.

Check T78.49XD with the rest of the claim: free scrubber

7th character "D": subsequent encounter

The appropriate 7th character is to be added to each code from category T78

A
initial encounter
D
subsequent encounter
S
sequela

Excludes1 inherited from the categories above T78.49XD

A category’s note binds every code beneath it.

Written on T78.4: Other and unspecified allergy

  • specified types of allergic reaction such as:
  • allergic diarrhea (K52.29)
  • allergic gastroenteritis and colitis (K52.29)
  • dermatitis (L23-L25, L27.-)
  • food protein-induced enterocolitis syndrome (K52.21)
  • food protein-induced enteropathy (K52.22)
  • hay fever (J30.1)

Excludes2 inherited from the categories above T78.49XD

Not part of this code, but both may be coded when both are present.

Written on T78: Adverse effects, not elsewhere classified

  • complications of surgical and medical care NEC (T80-T88)

Other codes that can never be billed with T78.49XD

Their own Excludes1 notes name this code, so the conflict is not listed above.

  • T75Other and unspecified effects of other external causes

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Medicare coverage

T78.49XD is named in 16 Medicare coverage policies: 16 listing it as supporting medical necessity. Which one applies depends on your Medicare contractor.

  • A56538Billing and Coding: Allergen Immunotherapy
  • A56558Billing and Coding: Allergy Testing
  • A56844Billing and Coding: RAST Type Tests
  • A57361Billing and Coding: Monitored Anesthesia Care

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under T78.49

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.