How does blind specimen testing work?
An employer or Consortium/Third Party Administrator (C/TPA) with a total of 2,000 or more DOT-regulated employees must send blind specimens to the laboratories that process its drug tests. The blind specimens, which are known positives, negatives, adulterated and substituted specimens, are sent to the laboratory with fictitious identifiers so that the laboratory can not distinguish them from employee specimens. They are submitted for quality control purposes.
