Definition - What does Substituted Specimen mean?
A substituted specimen is any substance that does not meet the expected characteristics of a valid test specimen because it is a replacement or false specimen.
When a proffered urine specimen fails to meet the creatinine and specific gravity values necessary to demonstrate that it is a normal human urine specimen, it is designated as a substituted specimen under the U.S. Department of Transportation's administrative provisions for drug and alcohol testing.
WorkplaceTesting explains Substituted Specimen
When a urine drug test is conducted, the test subject provides a urine sample which is usually split into two specimens for testing. As a preliminary step, one of these specimens will be subject to a specimen validity test (SVT) to ensure that the proffered sample has the characteristics of human urine. The two primary characteristics that a SVT examines are the creatinine level and specific gravity of the specimen. If the specimen fails to fall within the expected parameters for these measures, then it is deemed to be a substitute specimen and the test may be invalidated.