"Because sweat can be collected only in limited quantities, there may not be sufficient specimen for repeat or confirmatory testing. Sweat is less susceptible to tampering or adulteration than is urine. The accuracy of sweat testing is not standardized. Its accuracy remains somewhat controversial (Watson et al., 2006). However, the sweat patch is used extensively in the criminal justice system, and its use to identify relapse or violations of conditions of probation has been upheld by the courts."


"Clinical Drug Testing in Primary Care," Technical Assistance Publication (TAP) 32, Substance Abuse and Mental Health Services Administration, Clinical Drug Testing in Primary Care (Rockville, MD: U.S. Departent of Health and Human Services, 2012), p. 22.