In simple words: This code indicates a follow-up visit for someone who has deliberately harmed themselves by taking an overdose of a bacterial vaccine (other than common ones like smallpox or tetanus).

This code describes a subsequent encounter for a patient who has intentionally poisoned themselves with a bacterial vaccine other than smallpox, BCG, typhoid and paratyphoid, cholera, plague, tetanus or diphtheria. A subsequent encounter is any encounter after the initial encounter for the injury.

Example 1: A patient is admitted to the hospital after intentionally overdosing on a pertussis vaccine in a suicide attempt. This is the initial encounter, which would be coded with T50.A92A. After stabilization, the patient is discharged and follows up with their primary care physician a week later. This follow-up visit is a subsequent encounter and is coded as T50.A92D., An individual intentionally injects themselves with an excessive dose of meningococcal vaccine. They are treated in the emergency room (initial encounter T50.A92A). They require a follow-up appointment with an infectious disease specialist a few days later to monitor for adverse effects. This follow-up visit would be coded as T50.A92D., A patient is seen in the emergency department after intentionally harming themself with a bacterial vaccine not otherwise specified. This is the second visit for this issue. The first visit was two weeks prior at an urgent care clinic. This encounter would be coded as T50.A92D as it is a subsequent encounter.

Documentation should clearly state the type of bacterial vaccine involved (if known), the intent of self-harm, and that it's a subsequent encounter related to the initial poisoning event. Details of the initial encounter, treatment provided, current symptoms, and the reason for the subsequent visit should also be documented. If there are any long-term effects from the poisoning, those should be documented as well.