A drug test is commonly a technical examination of urine, blood, semen, sweat, or oral fluid samples to determine the presence or absence of specified drugs or their metabolized traces.
While SAMHSA/NIDA guidelines only allow laboratories to report quantitative results for the "NIDA-5" on their official NIDA tests, many drug testing laboratories and on-site tests also offer a wider or "more appropriate" set of drug screens which may be more reflective of current drug abuse patterns. As noted above, these tests include synthetic pain killers such as Oxycodone, Oxymorphone, Hydrocodone, Hydromorphone, benzodiazepines (Valium, Xanax, Klonopin, Restoril) and barbiturates in other drug panels (a "panel" is a predetermined list of tests to run). The confirmation test (usually GC/MS, or LC/MS/MS) can tell the difference between chemically similar drugs such as methamphetamine and methylenedioxymethamphetamine (MDMA or ecstasy), and in the absence of detectable amounts of methamphetamine in the sample, the lab will either report the sample as negative or report it as positive for MDMA. What the lab reports to the client depends upon whether MDMA was included in the panel as something to be tested for.
Gamma-hydroxy-butyrate (GHB) was not routinely tested for in the early 1990s, but due to increasing use, some laboratories have added it as an optional test. GHB is rare in pre-employment screening, but is commonly checked for in suspected cases of drug overdose, date rape, and post-mortem toxicology tests. Ketamine (Special K) may or may not be tested for, depending upon the preferences of the entity paying for the test, though testing for it is uncommon. In general, the greater the number of drugs targeted, the higher the cost of the test, which means that many employers only target the NIDA 5 for financial reasons.
Other drugs, such as meperidine (Demerol), fentanyl, propoxyphene, and methadone are not commonly tested for in most pre-employment situations. These drugs are more likely to be included in tests for certain demographic groups (such as healthcare workers, drug rehab patients, etc.)
|Alcohol||3–5 days via ethyl gluconoride (EtG) metabolite or 10–12 hours via traditional method||lifetime of hair||12 hours|
|Amphetamines (except meth)||1 to 2 days||up to 90 days||12 hours|
|Methamphetamine||2 to 4 days||up to 90 days||24 hours|
|Barbiturates (except phenobarbital)||2 to 3 days||up to 90 days||1 to 2 days|
|Phenobarbital||7 to 14 days||up to 90 days||4 to 7 days|
|Benzodiazepines||Therapeutic use: 3 days. Chronic use (over one year): 4 to 6 weeks||up to 90 days||6 to 48 hours|
|Cannabis|| ||Up to 90 days||12 hours|
|Cocaine||2 to 4 days with exceptions for certain kidney disorders||up to 90 days||24 hours|
|Codeine||1 day||up to 30 days||12 hours|
|Cotinine (a break-down product of nicotine)||2 to 4 days||up to 90 days||2 to 4 days|
|Morphine||2 days||up to 90 days||6 hours|
|Heroin||2 days (single use) 2-5 (chronic)||up to 90 days||6 hours|
|LSD||2 to 24 hours||up to 3 days||0 to 3 hours|
|Methadone||3 days||up to 30 days||24 hours|
|PCP||14 days; up to 30 days in chronic users||up to 90 days||24 hours|
The efficacy of urine testing is debatable due to systematic cheating. It is widely reported that sample substitution and adulteration occur frequently, and both are effective methods of avoiding would-be positive tests. There are a number of adulterant "masking" agents that are sold, though they are often nothing more than a simple diuretic and are rarely more effective than caffeine. Some people drink copious amounts of water to successfully dilute the concentration of drug metabolites in their urine below detectable thresholds. Often this results in clear samples that may be rejected on the grounds of being too dilute, although a complex B vitamin will make urine yellow despite this practice of waterloading. Specific gravity testing can be done to identify whether or not the sample is of dilute nature, though this is used infrequently on otherwise inconspicuous samples. Vitamin B3 (niacin) is also frequently used for its reported "flushing" effect, though this is also of disputable adeptness. Some types of urinalysis can detect the use of these "detox" products, though they are rarely used unless some facet of the sample is suspicious. Also, the wide availability of at home drug screens allows an individual to take their own test before they receive one, thus knowing the results ahead of time- giving the user further opportunity to dilute the sample or to find a substitute.Yeast can be detected 9 to 11 days after consumption but will not show levels consumed.
Additionally for pre-employment hair testing, the inability to obtain a sample may be grounds for not hiring the individual. Hair Testing labs are regulated by CLIA or SAMHSA (not FDA). There is a growing trend in major companies and law enforcement agencies to utilize hair analysis on account of its efficiency and reputation as the gold standard when considering test accuracy. This technology makes use of radioimmunoassay or the more modern ELISA technology with subsequent confirmation by mass spectrometry.
In recent years, hair testing has been the subject of a number of lawsuits. Studies have shown that different ethnic groups have different hair structure, potentially leading to false positives.
Shampoos are available to help subjects pass tests, however almost all of the products are just Aloe rid clarifying shampoo some with laundry detergent added. The aloe rid will help during detoxing to cut down on second-hand contamination from sweat and scalp oils. A two-step process that opens the cuticle layer and allows deeper penetration is used.
Tests detecting both FAEE and EtG levels have been used by UK courts. Hair Alcohol Testing was first commercialised by Trimega Laboratories of London.
Analysis of hair samples has many advantages as a preliminary screening method for the presence of toxic substances deleterious to health after exposures in air, dust, sediment, soil and water, food and toxics in the environment. The advantages of hair analysis include the non-invasiveness, low cost and the ability to measure a large number of, potentially interacting, toxic and biologically essential elements. Hence, head hair analysis is now increasingly being used as a preliminary test to see whether individuals have absorbed poisons linked to behavioral health problems.
The use of hair alcohol analysis to establish and verify persistent alcohol abusers within the United Kingdom has steadily increased in recent years.
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 millimeters 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 interpretated in a similar fashion as scalp hair (Hartwig et al., 2003b).
Extensive studies involving over 1000 donors have been carried out since 2000. These have enabled us to establish reliable reference ranges for FAEEs with respect to drinking habits of the various groups: non-drinkers < 0,4 ng/mg Excessive drinkers > 1ng/mg. Such practices however, may provide disputable results given that to define an individual as an 'excessive drinker' this would need to define a specific alcohol intake [in units]. Since the way an individual metabolises alcohol varies from person to person, the same quantity of alcohol in units would have varying effects from person to person. It is also not scientifically possible to equate a level of metabolite detected in an individual to a quantity of alcohol as a result of individual differences in metabolism.
Literature Pragst F., Balikova M.A.: State of the art in hair analysis for detection of drugs and alcohol abuse; Clinica Chimic Acta 370 2006 17-49.
Auwärter V.: Fettsäureethylester als Marker exzessiven Alkoholkonsums – Analytische Bestimmung im Haar und in Hautoberflächenlipiden mittels Headspace-Festphasenmikroextraktion und Gaschromatographie-Massenspektrometrie. Dissertation Humboldt-Universität Berlin 2006.
Pragst F., Auwärter V., Kiessling B., Dyes C.: Wipe-test and patch-test ror alcohol misuse based on the concentration ratio of fatty acid ethyl esters and squalen CFAEE/CSQ in skin surface lipids. Forensic Sci Int 2004; 143:77-86.
Detection in saliva tests begins immediately upon use:
One of the first steps for all drug tests is to make the sample testable. Urine and oral fluid can be used "as is" for some tests, but other tests require the drugs to be extracted from urine beforehand. Strands of hair, patches, and blood must be prepared before testing. Hair is washed in order to eliminate second-hand sources of drugs on the surface of the hair, then the keratin is broken down using enzymes. Blood plasma may need to be separated by centrifuge from blood cells prior to testing. Sweat patches are opened up and the sweat collection component is soaked in a solvent to dissolve any drugs present.
Laboratory-based drug testing is done in a two-tiered fashion using two different types of detection methods. The first is known as the screening test, and this is applied to all samples that go through the laboratory. The second, known as the confirmation test, is only applied to samples that test positive during the screening test. Screening tests are usually done by immunoassay (EMIT, ELISA, and RIA are the most common). A "dipstick" drug testing method which could at some future time provide screening test capabilities to field investigators has been developed at the University of Illinois. Screening tests are typically less sensitive and more prone to false positives and false negatives than the confirmation test.
After a suspected positive sample is detected during screening, the sample is flagged and tested using the confirmation test. Samples that are negative on the screening test are discarded and reported as negative. The confirmation test in most laboratories (and all SAMHSA certified labs) is performed using mass spectrometry, and is extremely precise but also fairly expensive to run. False positive samples from the screening test will be negative on the confirmation test. Samples testing positive during both screening and confirmation tests are reported as positive to the entity that ordered the test. Most laboratories save positive samples for some period of months or years in the event of a disputed result or lawsuit. For workplace drug testing, a positive result is generally not confirmed without a review by a Medical Review Officer that will normally interview the subject of the drug test.
The goal of random testing is to discourage drug use among employees, inmates, or students by not telling anyone who or when or where they are to be tested in advance. However, critics claim that random drug testing introduces a presumption of guilt, and is a violation of privacy if the drug user is not actually intoxicated during working hours. In addition, random testing is more likely to catch cannabis users, since THC metabolites are fat soluble and have a longer duration in the body than those of many other drugs. It has been suggested that this indirectly encourages the use of much more dangerous and harmful drugs that are excreted from the body faster.
It should be noted that in most areas, blood testing is the only legally defensible means for detecting drug use after an incident, although saliva testing is gaining acceptance. The sample should follow chain of custody requirements and should always be sent to a lab after collection. Positive on-site tests that may affect an employee's position or situation should always be followed up with a laboratory test before any action is taken against the employee. Laboratory tests (urine or blood) are the only legally recognized tests in most states as well as in most non-U.S. countries.
The main disadvantage of saliva based drug testing is a difficulty in detecting some drug types such as benzodiazepines and marijuana with sufficient accuracy using point of care equipment. Although detecting impairment is one of the major advantages, it is not necessarily the case that all impaired people will correctly be identified as positive using a saliva test when they should. Another disadvantage is that saliva is a potentially infectious medium and can harbour infection and disease. Accordingly, saliva specimens need to be handled with considerable care.
The main disadvantage of spray or sweat based drug testing is the fact that they are open to contamination. Also large variations of sweat production rates of possible donors make some results inconclusive. There is not much variety in these drug tests since they are not as popular as urine or saliva drug testing kits. Their prices tend to be higher per test conducted. One main disadvantage of this testing method is the limited number of drugs that can be detected.
It costs more than urine testing, and one must have a lab for results.
The second route was more recently constructed and originated in an incident that occurred in the US Navy. After a plane crashed onto the carrier deck of the USS Nimitz in 1981, killing and injuring dozens of personnel, drug testing was instituted immediately. The results revealed a large substance-abusing cohort within the ranks of enlisted persons and officers. As a result of this single incident, the Secretary of the Navy instituted an intensive drug testing and regulation program. These interventions were then adopted by other branches of the service over a three-year period. From these actions was derived the concept of a "drug-free workplace". In consultation with his drug-czar, Dr. Carlton Turner, President Ronald Reagan issued Executive Order 12584. In so doing he instituted mandatory drug-testing for all safety-sensitive executive-level and civil-service Federal employees. This was challenged in the courts by the Natl. Treasury Employees Union. In 1988 , this challenge was considered by the US Supreme Court. In this case the Court upheld the President's order A similar challenge resulted in the Court extending the drug-free workplace concept to the private sector. These decisions were then incorporated into the White House Drug Control Strategy directive issued by President George HW Bush in 1989.