Urine drug screen
When an employer requests a drug test from an employee, or a physician requests a drug test from a patient, the employee or patient is typically instructed to go to a collection site or their home. The patient or employee’s urine is collected at a remote location in a specially designed secure cup, sealed with tamper-resistant tape, and sent via express delivery service to a testing laboratory to be screened for drugs (typically SAMHSA 5 panel). The first step at the testing site is to split the urine into two aliquots. One aliquot is first screened for drugs using an analyzer that performs immunoassay as the initial screen. If the urine screen is positive then another aliquot of the sample is used to confirm the findings by gas chromatography – mass spectrometry (GC-MS) methodology. If requested by the physician or employer, certain drugs are screened for individually; these are generally drugs part of a chemical class that are, for one of many reasons, considered more abuse-prone or of concern. For instance, this is, due to their wide recreational use (much more than similar drugs), done to oxycodone and diamorphine, both sedative analgesics. If such a test is not requested specifically, the more general test (in the preceding case, the test for opiates) will detect the drugs, but the employer or patient will not have the benefit of the identity of the drug.
Employment-related test results are relayed to an MRO (Medical Review Office) where a medical physician reviews the results. If the result of the screen is negative, the MRO informs the employer that the employee has no detectable drug in the urine. However, if the test result of the immunoassay and GC-MS are non-negative and show a concentration level of parent drug or metabolite above the established limit, the MRO contacts the employee to determine if there is any legitimate reason – such as a medical treatment or prescription. If the test results are for other reasons, the testing laboratory will instead contact the physician who ordered the test.
On-site instant drug testing is becoming more widely used in those jurisdictions allowing it (such as some states of the USA) as a more cost-efficient method of effectively detecting drug abuse amongst employees, as well as in rehabilitation programs to monitor patient progress. These instant tests can be used for both urine and saliva testing. Although the accuracy of such tests varies with the manufacturer, some kits boast extremely high rates of accuracy, correlating closely with laboratory test results.
 Hair testing
Main article: Hair analysis
Hair analysis to detect drugs of abuse have been used by UK and Canadian courts, and hair testing for alcohol markers is now recognised in both the UK and US judicial systems. There are guidelines for hair testing that have been published by the Society of Hair Testing that specify the markers to be tested for and the cutoff concentrations that need to be tested. There are only a few UKAS ISO17025 accredited laboratories in the UK including Tricho Tech based in Cardiff and Alpha Biolaboratories based in Warrington, UK. Drugs of abuse that can be detected include Cannabis, Cocaine, Amphetamines and drugs new to the UK such as Mephedrone.
The hair follicle test is growing in popularity because it is less invasive than a urine screen, it is harder to falsify or tamper with the specimen, and the detection window is extended to roughly three months. Hair for testing can be collected from anywhere on the body, so the test can be utilized even when someone is bald or shaves their head. Because body hair grows at a different rate than head hair, some people[who?] have made the correlation that drug use can be detected in body hair for up to 12 months.
In contrast to other drugs consumed, alcohol is not deposited directly in the hair. For this reason the investigation procedure looks for direct products of ethanol metabolism. The main part of alcohol is oxidized in the human body. This means it is released as water and carbon dioxide. One part of the alcohol reacts with fatty acids to produce esters. The sum of the concentrations of four of these fatty acid ethyl esters (FAEEs: ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) are used as indicators of the alcohol consumption. The amounts found in hair are measured in nanograms (one nanogram equals only one billionth of a gram), however with the benefit of modern technology, it is possible to detect such small amounts. In the detection of ethyl glucuronide, or EtG, testing can detect amounts in picograms (one picogram equals 0.001 nanograms).
However there is one major difference between most drugs and alcohol metabolites in the way in which they enter into the hair: on the one hand like other drugs FAEEs enter into the hair via the keratinocytes, the cells responsible for hair growth. These cells form the hair in the root and then grow through the skin surface taking any substances with them. On the other hand the sebaceous glands produce FAEEs in the scalp and these migrate together with the sebum along the hair shaft (Auwärter et al., 2001, Pragst et al., 2004). So these glands lubricate not only the part of the hair that is just growing at 0.3 mm per day on the skin surface, but also the more mature hair growth, providing it with a protective layer of fat.
FAEEs (nanogram = one billionth of a gram) appear in hair in almost one order of magnitude lower than (the relevant order of magnitude of) EtG (picogram = one trillionth of a gram). It has been technically possible to measure FAEEs since 1993, and the first study reporting the detection of EtG in hair was done by Sachs in 1993.
In practice, most hair which is sent for analysis has been cosmetically treated in some way (bleached, permed etc.). It has been proven that FAEEs are (surprisingly) not significantly affected by such treatments (Hartwig et al., 2003a). FAEE concentrations in hair from other body sites can be interpreted in a similar fashion as scalp hair (Hartwig et al., 2003b).