T45.AX4DUpcomingBillable / specificExempt from present-on-admission reporting

Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, subsequent encounter

Chapters 19 · Inherited instructions

Use additional code

code to identify any retained foreign body, if applicable (Z18.-)

T36-T50 · Inherited instructions

Code first

, for adverse effects, the nature of the adverse effect, such as:
adverse effect NOS (T88.7)
aspirin gastritis (K29.-)
blood disorders (D56-D76)
contact dermatitis (L23-L25)
dermatitis due to substances taken internally (L27.-)
nephropathy (N14.0-N14.2)

Use additional code

code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
underdosing of medication regimen (Z91.12-, Z91.13-)

Excludes 1

toxic reaction to local anesthesia in pregnancy (O29.3-)

T45 · Inherited instructions

A — initial encounter

D — subsequent encounter

S — sequela

T45.A · Inherited instructions

Excludes 1

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

Excludes 2 · 7

Chapters 19 · Injury, poisoning and certain other consequences of external causes (S00-T88)

Excludes 2

birth trauma (P10-P15)
obstetric trauma (O70-O71)

T36-T50 · Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)

Excludes 2

abuse and dependence of psychoactive substances (F10-F19)
abuse of non-dependence-producing substances (F55.-)
immunodeficiency due to drugs (D84.821)
drug reaction and poisoning affecting newborn (P00-P96)
pathological drug intoxication (inebriation) (F10-F19)

Claims & coverage

Coverage depends on the payer, service and applicable policy. A billable code does not guarantee payment.

When ICD-10-CM is required

For US diagnosis claims covered by HIPAA, ICD-10-CM is required from October 1, 2015.

Use the service date for outpatient/professional claims and the discharge date for hospital inpatient claims. Earlier encounters use ICD-9-CM; each individual code must also be valid for the applicable date.

Official coding guidelines → · CMS ↗

Check Medicare coverage ↗

First observed · 2024-10-01

Code history

Latest recorded change · FY2025 · 04-01

ChangedUnchanged

FY2025 · 04-01

Effective from 2025-04-01

Inherited rules changed

Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, subsequent encounter

Billable diagnosis code

CDC/NCHS · FY2025 · 04-01

All editions (5)

All editions	Effective from	Code history
FY2025	2024-10-01	Added
FY2025 · 04-01	2025-04-01	Inherited rules changed
FY2026	2025-10-01	No tabular change
FY2026 · April	2026-04-01	No tabular change
FY2027	2026-10-01	No tabular change

Code-level instructions

The official Tabular List has no additional instructions at this code level.

Review the instructions inherited from its parent categories below. Inherited instructions ↓

Review the official coding guidelines ↗

Inherited instructions

Chapters 19 · Injury, poisoning and certain other consequences of external causes (S00-T88)

Excludes 2

birth trauma (P10-P15)
obstetric trauma (O70-O71)

Use additional code

code to identify any retained foreign body, if applicable (Z18.-)

Note

Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

T36-T50 · Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)

Includes

adverse effect of correct substance properly administered
poisoning by overdose of substance
poisoning by wrong substance given or taken in error
underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed

Excludes 1

toxic reaction to local anesthesia in pregnancy (O29.3-)

Excludes 2

abuse and dependence of psychoactive substances (F10-F19)
abuse of non-dependence-producing substances (F55.-)
immunodeficiency due to drugs (D84.821)
drug reaction and poisoning affecting newborn (P00-P96)
pathological drug intoxication (inebriation) (F10-F19)

Code first

, for adverse effects, the nature of the adverse effect, such as:
adverse effect NOS (T88.7)
aspirin gastritis (K29.-)
blood disorders (D56-D76)
contact dermatitis (L23-L25)
dermatitis due to substances taken internally (L27.-)
nephropathy (N14.0-N14.2)

Use additional code

code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
underdosing of medication regimen (Z91.12-, Z91.13-)

Note

The drug giving rise to the adverse effect should be identified by use of codes from categories T36-T50 with fifth or sixth character 5.

T45 · Poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified

Seventh character

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

A — initial encounter

D — subsequent encounter

S — sequela

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

Excludes 1

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

Official conversion history

Historical assignments from the CDC conversion table support data retrieval. They do not authorize substituting a previous code for the current code.

Release dates 2024-10-01

Previous assignment: T45.1X4D

Related codes

Other entries in the same category; these are not automatic substitutes.

Code	Description	Category · further specificity required
T45.AX4A	Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, initial encounter	Billable / specific
T45.AX4S	Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, sequela	Billable / specific

Official titles and instructions are preserved in their source language. Official sources ↗

T45.AX4DUpcomingBillable / specificExempt from present-on-admission reporting

Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, subsequent encounter

Chapters 19 · Inherited instructions

Use additional code

code to identify any retained foreign body, if applicable (Z18.-)

T36-T50 · Inherited instructions

Code first

, for adverse effects, the nature of the adverse effect, such as:
adverse effect NOS (T88.7)
aspirin gastritis (K29.-)
blood disorders (D56-D76)
contact dermatitis (L23-L25)
dermatitis due to substances taken internally (L27.-)
nephropathy (N14.0-N14.2)

Use additional code

code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
underdosing of medication regimen (Z91.12-, Z91.13-)

Excludes 1

toxic reaction to local anesthesia in pregnancy (O29.3-)

T45 · Inherited instructions

A — initial encounter

D — subsequent encounter

S — sequela

T45.A · Inherited instructions

Excludes 1

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

Excludes 2 · 7

Chapters 19 · Injury, poisoning and certain other consequences of external causes (S00-T88)

Excludes 2

birth trauma (P10-P15)
obstetric trauma (O70-O71)

T36-T50 · Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)

Excludes 2

abuse and dependence of psychoactive substances (F10-F19)
abuse of non-dependence-producing substances (F55.-)
immunodeficiency due to drugs (D84.821)
drug reaction and poisoning affecting newborn (P00-P96)
pathological drug intoxication (inebriation) (F10-F19)

Claims & coverage

Coverage depends on the payer, service and applicable policy. A billable code does not guarantee payment.

When ICD-10-CM is required

For US diagnosis claims covered by HIPAA, ICD-10-CM is required from October 1, 2015.

Official coding guidelines → · CMS ↗

Check Medicare coverage ↗

First observed · 2024-10-01

Code history

Latest recorded change · FY2025 · 04-01

ChangedUnchanged

FY2025 · 04-01

Effective from 2025-04-01

Inherited rules changed

Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, subsequent encounter

Billable diagnosis code

CDC/NCHS · FY2025 · 04-01

All editions (5)

All editions	Effective from	Code history
FY2025	2024-10-01	Added
FY2025 · 04-01	2025-04-01	Inherited rules changed
FY2026	2025-10-01	No tabular change
FY2026 · April	2026-04-01	No tabular change
FY2027	2026-10-01	No tabular change

Code-level instructions

The official Tabular List has no additional instructions at this code level.

Review the instructions inherited from its parent categories below. Inherited instructions ↓

Review the official coding guidelines ↗

Inherited instructions

Chapters 19 · Injury, poisoning and certain other consequences of external causes (S00-T88)

Excludes 2

birth trauma (P10-P15)
obstetric trauma (O70-O71)

Use additional code

code to identify any retained foreign body, if applicable (Z18.-)

Note

Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

T36-T50 · Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)

Includes

adverse effect of correct substance properly administered
poisoning by overdose of substance
poisoning by wrong substance given or taken in error
underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed

Excludes 1

toxic reaction to local anesthesia in pregnancy (O29.3-)

Excludes 2

abuse and dependence of psychoactive substances (F10-F19)
abuse of non-dependence-producing substances (F55.-)
immunodeficiency due to drugs (D84.821)
drug reaction and poisoning affecting newborn (P00-P96)
pathological drug intoxication (inebriation) (F10-F19)

Code first

, for adverse effects, the nature of the adverse effect, such as:
adverse effect NOS (T88.7)
aspirin gastritis (K29.-)
blood disorders (D56-D76)
contact dermatitis (L23-L25)
dermatitis due to substances taken internally (L27.-)
nephropathy (N14.0-N14.2)

Use additional code

code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
underdosing of medication regimen (Z91.12-, Z91.13-)

Note

The drug giving rise to the adverse effect should be identified by use of codes from categories T36-T50 with fifth or sixth character 5.

T45 · Poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified

Seventh character

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

A — initial encounter

D — subsequent encounter

S — sequela

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

Excludes 1

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

Official conversion history

Historical assignments from the CDC conversion table support data retrieval. They do not authorize substituting a previous code for the current code.

Release dates 2024-10-01

Previous assignment: T45.1X4D

Related codes

Other entries in the same category; these are not automatic substitutes.

Code	Description	Category · further specificity required
T45.AX4A	Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, initial encounter	Billable / specific
T45.AX4S	Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined, sequela	Billable / specific

Official titles and instructions are preserved in their source language. Official sources ↗