This presentation provides an overview and historical perspective of Sample Validity Testing (SVT) in the U.S. It begins with a brief historical overview including: urine specimen tampering practices and identified adulterant and substitution products, the evolution of laboratory procedures for SVT, and the implementation of regulatory policies. As an example, the National Laboratory Certification Program or NLCP under the U.S. Department of Health and Human Services, Division of Workplace Programs in SAMHSA is presented. Next, the effects of several “model” adulterants are discussed. Lastly, current specimen validity evaluation approaches such as measurement of specimen temperature, physical characteristics, creatinine, specific gravity, pH, and oxidizing adulterants such as chromium, glutaraldehyde, pyridine and nitrite are discussed.