The presence of drugs in sweat was first detected about the same time when quinine was detected, in 1844. Morphine, being the first ever detected drug of abuse in sweat, was reported in 1842 and then came amphetamines in record in about 1972. Since the 1950s, the sweat is being collected, analyzed and studied comprehensively, since it is a major means to identify cystic fibrosis (an increased salt seepage in sweat due to a defect in chloride ion channel) in patients. A number of writings on the techniques for sweat collection can be found today, due to its clinical usefulness. Many sweat collection techniques such as wiping, blotting, occlusive patches, iontophoresis with pilocarpine stimulated secretions, and the use of capillary tubes, can today be found in black and white because of its clinical usefulness. Swabbing the skin in order to detect the presence of drugs may contaminate the skin from the drugs present in the atmosphere, rather than reflecting the ingested drugs released in sweat. In 1980s, the ethanol sweat tests were launched; however, the availability of completely occlusive devices was a limitation in order to avoid evaporation. The test was not practical for regular use as the fully occlusive patches could cause bacterial growth and skin irritation.
In 1981, the 3M developed “TegardermTM”, a wound dressing which is gas permeable, which led to the development of a sweat collection device, with a useful life of a number of days. The PharmCheck sweat patch that uses the Tegarderm dressing material was finally approved by FDA in 1992, as a medical sweat collection device. In mid 1990s, the FDA also approved the immunoassay tests, conducted for the analysis of the extracts from the sweat patch. Presently, more than a 100 scientific publications on drug detection in sweat exists.
Department of Health and Human Services (DHHS), an integral part of SAMHSA, initiated federal workplace drug-testing programs using the sweat patch device in 2004. They then reviewed the documented research on the sweat patch and the chances of external contamination in particular, before concluding the following: “the DHHS believes that under normal circumstances, absorption of drug from the external environment into the body through the outer layer is very much unlikely. Moreover, the scientific advancements in techniques to detect drugs such as use of oral fluid, head hair and sweat has enabled them to be used with same confidence in federal programs as with the use of urine. At last, numerous federal and state courts have found the sweat patch as a reliable and accurate resource to detect usage of drugs. It can be evidenced by the US 8th Circuit Court of Appeals decision in the recently decided case of United States vs. Meyer, which ruled: “Today, we join the other courts that have previously determined that sweat patch results are a generally reliable method of determining whether an offender has violated a condition of his or her probation”.