Blind Ideally . All samples should be labeled with a number, not a person's name, when sent to the testing laboratory. Standards should be indistinguishable from the unknowns so that the lab is not explicitly careful just when processing the standards. Additionally, the testing laboratory should receive no correspondence concerning which specimens the company suspects might be positive. DOT rules .
Blind testing is used at two levels.
In addition, the standards are to be labeled in ways that make them appear as ordinary samples. In science, the penalty for being caught falsifying evidence is complete and total ostracization from the scientific community. Drug tests are different because there are no repeated cycles of evaluation and revision. That is, if your blood or urine tests positive by a fraudulent procedure, the authorities will not come to you later and take another sample to confirm the result. It is thus imperative that procedures be implemented to guard against falsification of test results.