Most Chain of Custody documents consist of a multi-part form and label combination with bar coding/numbering. The form contains all the history of a project, and can be a laser, snap out, or continuous format. The label is used for tracking any portion that may be transferred away from the history. The label can be a variety of stocks depending on the application and what the label is to be applied to.  The bar coding/numbering traces the two back to each other and is on both the form and the label. There is a variety of symbology that can be used for the bar coding and is usually 8 or 10 digit crash Arabic numbering.

Accuracy is a very important function of a solid Chain of Custody procedure, because a good form carries reliable and defendable documentation. For example, if you have a drug testing Chain of Custody form for laboratory testing, making sure that the numbers are all the same on each form, and that the label will not fall off the tube is very important. Having a wrong number on the form could cause the test results to be traced back to the wrong person.