Final answer:
A single DD Form 2624 is included with a box of urine samples to document the chain of custody, which is critical for maintaining the legal admissibility of the samples collected for military drug testing programs.
Step-by-step explanation:
The DD Form 2624, officially titled Forensic Toxicology Drug Testing Laboratory Chain of Custody, is used to document the control, transfer, handling, and analysis of each urine sample collected for military drug testing programs. When shipping a box of urine samples, a single DD Form 2624 is included with that shipment. This form is extremely important as it maintains the integrity of the samples, ensuring that the results are legally admissible. The DD Form 2624 accompanies the urine samples from the point of collection through to the laboratory and then to the final review and reporting process.