Is T45.AX4S a billable ICD-10-CM code?

Yes. T45.AX4S is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does T45.AX4S 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.AX4S?

T45.AX4S 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.AX4S (T45.A) and apply to it just the same.

T45.AX4S

T45.AX4S — Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, sequela

Billable / specific codeICD-10-CMPOA exempt

T45.AX4S is a billable, specific ICD-10-CM code for poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, sequela. It is valid for submission on a claim.

7th character "S" — sequela

The appropriate 7th character is to be added to each code from category T45

A: initial encounter
D: subsequent encounter
S: sequela

Excludes1 inherited from the categories above T45.AX4S

These are not written on T45.AX4S, but they bind it: a note on a category applies to every code beneath it. Billing T45.AX4S 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.AX4S 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.

Medicare coverage

T45.AX4S is named in 2 Medicare coverage policies — 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A56948Billing and Coding: Lab: Cystatin C Measurement
A57657Billing and Coding: Sedimentation Rate, Erythrocyte

Code history

What changed, and when. Derived by diffing consecutive CMS release files — which matters when you are defending a code assigned under an earlier edition.

addedFY2024-FY2027
Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, sequela

Related codes at this level

Codes that share T45.AX4. If T45.AX4S is not quite right, the correct code is usually one of these.

Questions about T45.AX4S

Is T45.AX4S a billable ICD-10-CM code?: Yes. T45.AX4S is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does T45.AX4S 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.AX4S?: T45.AX4S 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.AX4S (T45.A) and apply to it just the same.