"The parent drug is usually found in oral fluids, although the metabolite(s) may be present and quite useful. The parent drug is generally found in higher concentrations in oral fluids than are drug metabolites. Compared with urine specimens, oral fluid specimens present fewer opportunities for adulteration or substitution (Dams, Choo, Lambert, Jones, & Huestis, 2007). Use of commercial adulterants or mouthwashes were not found to interfere with the immunoassay (Bosker & Huestis, 2009), or they did not affect test results if the products are used more than 30 minutes before specimen collection (Drummer, 2006; Niedbala, Kardos, & Fries, et al., 2001; Niedbala, Kardos, Fritch, Cannon & Davis, 2001). The window of detection for oral fluid is narrower than it is for urine, and drug concentrations are generally lower (Warner, 2003). In general, drug testing of oral fluids detects drug use during the previous 24–48 hours, regardless of the route of administration (Cone, 2006), although the selection of cutoffs plays an important role in the length of the detection window.
"Oral fluid collection devices vary, but the most common version is a swab or absorbent pad on a stick that is placed between the lower cheek and gums to collect fluid and is left in place for a few minutes. It is then inserted into a vial containing a buffer solution for shipment to the laboratory. POCTs [Point Of Care Tests] are also available for oral fluid testing."

"The results of this investigation provide further support to the possibility of using exhaled breath as a readily available specimen for drugs of abuse testing. There is a possibility that exhaled breath will develop into a new matrix for routine drug testing and present an alternative to already used matrices like urine, blood, oral fluid, sweat and hair. Each matrix may have its specific advantages and disadvantages. Since exhaled breath may be as easy to collect as in alcohol breath testing, it may present a new, more accessible matrix than blood at the roadside and elsewhere when the sampling procedure is an obstacle. We previously observed that exhaled breath methadone increases after intake [2]. If a correlation to blood concentration can be shown for exhaled breath levels, it may become a substitute matrix for monitoring impairment. One advantage of exhaled breath may be the detection of 6-AM, which is problematic in blood."

"Like hair, fingernails and toenails are composed of a hard protein called keratin. Drugs are incorporated into nails from the blood stream and remain locked in the nail as it grows. Nails grow in both length and thickness. Drugs enter the nail from the base (cuticle end) as the keratin is formed and via the nail bed that extends under the full length of nail.
"The distal end or free end of the fingernails and toenails are clipped for testing. If length does not allow, the surface can be shaved but is not the preferred sample. If the surface is scrapped using a razor blade (a medical device) then this one procedure probably requires the collector to follow HIPAA requirements. Nail polish and acrylic nails must be removed prior to collecting the nail sample.
"The method of screening for drug use in nail tests is the same as hair, Immunoassay. The nail is put in a chemical solution to remove external contaminants and then liquefied. All drugs found in the initial screen are confirmed by one of the methods previously explained.
"Drugs can be identified in nail clippings 2-4 weeks following ingestion and can be detected from 3 to 8 months or longer. The broad range is based on numerous factors. Fingernails grow (approximately .12 inches per month) faster than toenails (approximately .042 inches per month), longer fingers grow faster than short fingers, age and gender of the person, the time of year, the food the person eats, the dominant hand grows faster than the other hand, etc."

"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."