A collection site is any facility equipped to collect urine, oral fluid, or other specimens in compliance with testing regulations: verified donor identification, a secured water source and bluing agent in the toilet for urine collections, specimen temperature checks within four minutes, sealed tamper-evident bottles initialed by the donor, and chain-of-custody documentation from the first moment. For DOT testing, collectors must complete qualification training and follow 49 CFR Part 40 procedures exactly — procedural mistakes at the collection site are a leading cause of cancelled tests. Employers with dispersed workforces typically need a network of collection sites near every work location rather than a single contracted clinic.