Adverse effect of vaccines and biological substances, init

This code identifies an unintended and undesirable reaction to a vaccine or other biological substance, excluding those specifically categorized elsewhere. It signifies the initial presentation of symptoms or the first time the patient is seen for this adverse event.

Apply this code when a patient experiences an adverse reaction to a vaccine (e.g., flu shot, tetanus shot) or other biological substance (e.g., antitoxin, immune globulin) that is not otherwise specified. This is appropriate for the initial visit where the adverse effect is diagnosed or treated.

• Always sequence this code first, followed by codes for the specific manifestation of the adverse effect.
• Do not use for poisoning, underdosing, or toxic effects; those have their own specific codes.
• Ensure documentation clearly states the substance involved and that the reaction is an adverse effect, not a therapeutic failure or complication of care.