Poisoning by fentanyl or fentanyl analogs, undet, subs

This code signifies a patient presenting for follow-up care or treatment of adverse effects resulting from fentanyl or fentanyl analog poisoning, where the intent (accidental, intentional self-harm, assault) of the poisoning could not be determined. It indicates that the initial acute phase of treatment for the poisoning has concluded, and the patient is now receiving ongoing management for its sequelae.

Apply this code when a patient is seen for continued care related to an undetermined fentanyl poisoning, such as managing withdrawal symptoms, addressing organ damage, or attending rehabilitation after the initial hospitalization. This would be used for any encounter after the initial acute treatment, where the cause of the poisoning remains unclear.

• Ensure documentation clearly states "undetermined" intent for the fentanyl poisoning.
• This code requires a 7th character "D" for subsequent encounter; do not use for the initial treatment.
• Always sequence this code as a primary diagnosis when it is the reason for the encounter, or as a secondary diagnosis if managing a complication of the poisoning.