Poisn by immune chkpt inhibtr/immunostim drugs, undet, subs

This code signifies an adverse effect or toxic reaction resulting from immune checkpoint inhibitors or other immunostimulant medications, where the intent of the poisoning (e.g., accidental, intentional self-harm) cannot be determined. This diagnosis is used when the patient is presenting for follow-up care or ongoing management of these poisoning effects.

Apply this code when a patient is seen for continued treatment, monitoring, or evaluation of complications arising from an undetermined poisoning by immune checkpoint inhibitors or immunostimulant drugs. This includes scenarios where the initial acute phase of treatment has passed, and the patient is now in a subsequent phase of care.

• Always assign an additional code for the specific manifestation(s) of the poisoning.
• Ensure documentation clearly supports "undetermined" intent and a "subsequent encounter" for ongoing care.
• Distinguish from initial encounters (A) or sequela (S) by carefully reviewing the encounter type.