Is T45.AX1 a billable ICD-10-CM code?

No. T45.AX1 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does T45.AX1 sit in the tabular list?

Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50).

What cannot be coded together with T45.AX1?

T45.AX1 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above T45.AX1 (T45.A) and apply to it just the same.

T45.AX1

T45.AX1 — Poisoning by immune checkpoint inhibitors and immunostimulant drugs, accidental (unintentional)

Non-billable headerICD-10-CM

T45.AX1 is a non-billable header ICD-10-CM code for poisoning by immune checkpoint inhibitors and immunostimulant drugs, accidental (unintentional). 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

Inclusion terms

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

Poisoning by immune checkpoint inhibitors and immunostimulant drugs NOS

Excludes1 inherited from the categories above T45.AX1

These are not written on T45.AX1, but they bind it: a note on a category applies to every code beneath it. Billing T45.AX1 with anything listed here is a denial.

Written on T45.A — Poisoning by, adverse effect of and underdosing of immune checkpoint inhibitors and immunostimulant drugs

poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drug (T45.1)

Risk adjustment

T45.AX1 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code history

T45.AX1 has not changed since FY2024 — no addition, revision or deletion across the FY2024–FY2027 ICD-10-CM releases.

Code to one of these instead T45.AX1

3 child codes. Green means billable.

Related codes at this level

Codes that share T45.AX. If T45.AX1 is not quite right, the correct code is usually one of these.

Questions about T45.AX1

Is T45.AX1 a billable ICD-10-CM code?: No. T45.AX1 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does T45.AX1 sit in the tabular list?: Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50).
What cannot be coded together with T45.AX1?: T45.AX1 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above T45.AX1 (T45.A) and apply to it just the same.