Answer:
The chain begins when the patient is identified.
Step-by-step explanation:
The Chain of Custody is a protocol that laboratories use to make sure that a sample is always under custody of the correct person and in the right place. During this process, all the steps and transactions of the sample from one person or location to the other have to be described and documented, from the moment of the extraction up to the moment of its disposal. So the first step is to identify the patient and have a record of this.