In general, Lab Investigations consists of three areas of functionality:

Area Description
Incident A "Planned" or "Unplanned" event. Unplanned events can be investigated, resulting in a "Finding".
Action Plan Plan to institute corrective and/or preventive actions in response to an Incident. There are two types of Action Plan:
Corrective Action (CA) defines the need to remedy the situation resulting from an Incident.
Preventive Action (PA) defines the need to ensure that the problem does not reoccur.
Workorder Mechanism that tracks tasks required to complete an Action Plan or Incident.

This is a high-level flow of these areas within the Lab Investigations module: