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T78.41

T78.41: Arthus phenomenon

Non-billable headerICD-10-CM

T78.41 is a non-billable header ICD-10-CM code for arthus phenomenon. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

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

A
initial encounter
D
subsequent encounter
S
sequela

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Arthus reaction

Excludes1 inherited from the categories above T78.41

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 T78.41

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 T78.41

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.

Alphabetic index entries that lead here

  • Arthus' phenomenon or reaction

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead T78.41

3 child codes. Green means billable.

Other codes under T78.4

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.