Poisoning by oth vaccines and biolg substances, undet, subs

This code signifies an adverse reaction or harmful effect resulting from a vaccine or other biological substance, where the intent of the poisoning is unknown. It is used when the patient is receiving active treatment for the sequelae of the poisoning, or during the recovery phase.

Apply this code for follow-up visits or ongoing treatment related to a poisoning by a vaccine or biological substance when the circumstances surrounding the exposure are not clear (e.g., accidental, intentional self-harm, assault, or therapeutic error cannot be determined). This includes situations where the patient is experiencing persistent symptoms or complications from the initial event.

• Always sequence this code after the primary diagnosis for the specific manifestation of the poisoning.
• Requires an additional code to specify the particular adverse effect or symptom experienced by the patient.
• Only use for subsequent encounters; for the initial encounter, use the corresponding "A" (initial encounter) seventh character.