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T45.1

T45.1: Poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drugs

Non-billable headerICD-10-CM

T45.1 is a non-billable header ICD-10-CM code for poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drugs. 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 T45

A
initial encounter
D
subsequent encounter
S
sequela

Excludes1: never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

  • poisoning by, adverse effect of and underdosing of immune checkpoint inhibitors and immunostimulant drugs (T45.A)
  • poisoning by, adverse effect of and underdosing of tamoxifen (T38.6)

Other codes that can never be billed with T45.1

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

  • T36Poisoning by, adverse effect of and underdosing of systemic antibiotics
  • T37.5Poisoning by, adverse effect of and underdosing of antiviral drugs
  • T45.APoisoning by, adverse effect of and underdosing of immune checkpoint inhibitors and immunostimulant drugs

Risk adjustment

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

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead T45.1

1 child code. Green means billable.

Other codes under T45

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.