ICD-10 Code T45.A: Poisoning by, adverse effect of and underdosing of immune checkpoint inhibitors and immunostimulant drugs

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Injury, poisoning and certain other consequences of external causes (S00-T88).

When is it used?

• May be used when a clinician documents poisoning by, adverse effect of and underdosing of immune checkpoint inhibitors and immunostimulant drugs in a patient's medical record.
• May appear in hospital records, claims, referrals, and clinical documentation.
• This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

• A code alone does not explain severity, treatment plan, or outcome.
• A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
• This entry may represent a broader category rather than the most specific billable code.

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Official coding notes

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

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