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General information
Drug "tests" can be divided into two general groups. The first group
is the kind most people are familiar with. This type of testing involves
the donor giving a sample of some bodily fluid or hair to an employer,
doctor, law enforcement official, or a died testing center. This is
normally a sample of
urine,
blood,
hair, or
saliva/ oral fluid. After collection from the donor, the sample is
sealed with a
tamper-evident seal and sent to a laboratory for analysis. The
disadvantages are typically costs associated with the need for
collection sites (urine, blood), and the delay in receiving results (up
to 4 days.)dthe availability of results within minutes. Furthermore, if
on-site screens, such as oral died or saliva tests are used, the problem
of "beating the tests" (otherwise known as sample adulteration or
substitution) can be virtually eliminated. On-site screens provide
qualitative results, and when supplemented with laboratory-based
confirmation tests, can be defended in a court of law.
This article will focus primarily on the first type of test, but will
refer to the latter when appropriate.
The NIDA 5
Drug testing in the United States basically began in the late 1980's
with the testing of certain federal employees and specified DOT
regulated occupations. Drug testing guidelines and processes, in these
areas exclusively, are established and regulated (by the
Substance Abuse and Mental Health Services Administration, formerly
under the direction of the
National Institute on Drug Abuse or NIDA) require that companies who
use professional drivers, specified safety sensitive transportation
and/or oil and gas related occupations, and certain federal employers,
test them for the presence of certain
drugs. These test classes were established decades ago, and include
five specific drug groups. They do not account for current drug
usage patterns. For example, the tests do not include "synthetic
opiates", such as oxycodone, oxymorphone, hydrocodone, hydromorphone,
etc., compounds that are highly abused in America:
- Cannabinoids (marijuana,
hashish)
-
Cocaine (cocaine, benzoylecognine, cocaethylene)
-
Amphetamines (amphetamine,
methamphetamine)
-
Opiates (heroin,
opium,
codeine,
morphine)
-
Phencyclidine (PCP)
While SAMHSA/NIDA guidelines only allow labs to report quantitative
results for the "NIDA-5" on their official NIDA tests, many drug testing
labs and on-site tests also offer a wider or "more appropriate" set of
drug screens which are 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
GCMS) can tell the difference between chemically similar drugs such
as methamphetamine and 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 labs 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 tested for, the
higher the price of the test, so many employers stick to 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.)
Hallucinogens other than cannabis and PCP, such as mushrooms (psilocybin),
LSD, and peyote (mescaline)
are rarely tested for.
Detection periods
The following chart gives approximate detection periods for each
substance by test type. The ranges depend on amount and frequency of
use, metabolic rate, body mass, age, overall health, and urine pH. For
ease of use, the detection times of metabolites have been incorporated
into each parent drug. For example, heroin and cocaine can only be
detected for a few hours after use, but their metabolites can be
detected for several days in urine. In this type of situation, we will
report the (longer) detection times of the metabolites.
- NOTE 1: Oral fluid or saliva testing results for the most part
mimic that of blood. The only exception is THC. Oral fluid will
likely detect THC from ingestion up to a maximum period of 18-24
hours.
- NOTE 2: Urine can not detect current drug use. It takes
approximately 6-8 hrs. post-consumption for drug to be metabolized
and excreted in urine. Similarly, hair requires two weeks, and
sweat, seven days.
| SUBSTANCE |
URINE |
HAIR |
BLOOD |
|
Alcohol |
6-12 hours days via Ethyl Gluconoride(EtG) metabolite |
12 hours |
|
Amphetamines (except meth) |
2 to 4 days |
up to 90 days |
12 hours |
|
Methamphetamine |
2 to 5 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 |
1 to 5 Weeks |
up to 90 days |
6 to 48 hours |
|
Cannabis |
1-30 days(1 to 3 days if the use is single, and up to 30
days in limited instances) |
up to 90 days |
2 days |
|
Cocaine |
1 to 3 days |
up to 90 days |
24 hours |
|
Codeine |
2 to 4 days |
up to 90 days |
12 hours |
|
Cotinine (a break-down product of
nicotine) |
2 to 4 days |
up to 90 days |
2 to 4 days |
|
Morphine |
2 to 3 days |
up to 90 days |
6 hours |
|
Heroin |
2 to 3 days |
up to 90 days |
6 hours |
|
LSD |
2 to 24 hours |
unknown |
0 to 3 hours |
|
PCP |
5 to 60 days |
up to 90 days |
24 hours |
Common types of drug tests
Urine drug screen
Also known as
urinalysis, this procedure requires that one provide a sample of
urine. Either a test card is used on site for immediate results (see
"General" section), or the sample is sent away to a lab to undergo
gas chromatography/mass
spectrometry (also known as GCMS),
high performance liquid chromatography or
immunoassay analysis. Sample substitution or adulteration have
become a significant issue in the United States due to the prevalence of
synthetic and/or drug-free urine and a wide range of adulterants on the
internet. Some people attempt to defeat a urine test by drinking copious
amounts of water, however, a sufficiently diluted sample may be rejected
due to its clear color. Samples that are too clear may be flagged and
tested for
specific gravity. If the sample fails the specific gravity test, the
sample is rejected and the dilution is reported to the entity that
ordered the test. Some
diuretics and herbal extracts, such as
goldenseal, are marketed as a quick "detox"
from
controlled substances, but their efficacy is questionable. Some
types of urinalysis can even detect the use of these "detox" products.
One of the methods to test for adulterants is to add some amount of an
actual drug to a small portion of the sample and then retest that
portion. If a masking agent is present in the urine, the resulting drug
test will have a negative result despite the fact that a drug was added.
This situation is also usually reported to whomever ordered the test.
Hair drug screen
Hair follicle testing is quite accurate and can go back 6 months or
longer, showing any controlled substances used in a sort of timeline. As
hair grows out, any drugs used are encased in the hair shaft, so the
longer the hair, the longer back in the individual's drug history the
lab can detect. Most legitimate testing facilities, however, only use
hair within about 3-5 cm of the scalp, and discard the rest. This limits
the detection history to about 90 days, depending upon the rate of
growth of the individual's hair. Some people attempt to circumvent this
through
shaving their heads. In the absence of the required amount of hair
on the scalp, body hair can be used as an acceptable substitute.
Additionally, for pre-employment hair testing, the inability to obtain a
sample may be grounds for not hiring the individual.
Saliva drug screen / Oral fluid-based drug screen
Saliva / oral fluid-based drug tests can generally detect use during
the previous few days. Saliva or oral fluid based drug tests are
becoming more prevalent because of their convenience and the fact that
they can not be adulterated. Furthermore, on-site oral based tests in
particular enable the implementation of random testing programs, proven
to be the most effective type of drug screening. Oral fluid based tests
are as accurate as urine and can be obtained from quality suppliers in
the United States. Testing is usually performed by employers, for either
pre-employment, random, post-accident, reasonable suspicion, or
return-to-duty testing. Oral fluid based testing most closely mimics
results found with blood and is preferable for detecting on-the-job drug
use or in post-accident applications in this case because the degree of
intoxication can be approximated based on the amount of substance in the
blood. The Victorian Police in Australia are also using random
saliva-tests to detect drivers under the influence of amphetamines and
cannabis. South Australian police were also given the power to drug-test
drivers from 2006.
Detection in saliva tests begins immediately upon use:
- Marijuana and Hashish (THC): 1 hour after ingestion, for up to
14 hours
- Cocaine (including crack): From time of ingestion for 48 to 72
hours
- Opiates: From time of ingestion for 48 to 72 hours
- Methamphetamine and Ecstasy (MDMA, "Crank," "Ice"): From time of
ingestion for 48 to 72 hours
- BZD: From time of ingestion for 48 to 72 hours
Sweat drug screen
Sweat tests are patches attached to the skin to collect sweat over a
long period of time (10-14 days). These are almost exclusively used by
child protective services, parole departments, and other government
institutions concerned with drug use over long periods, when urine
testing is not practical. The patches have security features that keep
them from being covertly removed and then reapplied without the
knowledge of the testing agency. At the end of the test period, the
patch is removed by a social worker or parole officer and sent to a lab
for analysis. If the person has used any drugs during the period that
the patch was in place, they will test positive for that drug. This type
of testing has fallen out of favor with government agencies due to
documented problems with certain drugs[citation needed]
.
Drug testing methodologies
Once the sample arrives at the lab for analysis, the different types
of drug tests are tested in very similar ways. Before testing the
sample, the
tamper-evident seal is checked for integrity. If it appears to have
been tampered with or was damaged in transit, the lab rejects the sample
and does not test it.
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 lab. 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.[1]
Screening tests are typically less sensitive and more prone to
false positives and
false negatives than the confirmation test.
Once 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 labs (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 labs save positive samples for some period
of months or years in the event of a disputed result or lawsuit.
Types of testing
Pre-employment drug testing
This is by far the most common type of drug test used by businesses.
It has the advantage of being inexpensive, since only one test per
employee needs to be paid for by the company. Furthermore, since most
pre-employment drug testing is urine-based and subject to sample
adulteration or substitution, the effectiveness of this approach has
been questioned by federal legislators. However, many Orginization's
have a witness in the room at the time of the testing
Random drug testing
This is the most controversial type of drug testing regimen. Some
also note that it is also the most effective method to deter drug use
[citation needed]. It is
usually used by
corporations, drug rehab centers,
prisons, military, U.S.Government (NASA) and more recently,
schools. This method may also be used on teens by their parents, or
mandated to be performed on teens at school. The point of a random drug
test is deterrence, as the threat of detection is much higher vs. other
testing methods[citation needed].
Companies use various ways of determining who gets tested, ranging from
drawing names out of a hat, to using more defensible methods such as
robust random number generators. The goal of this test is to discourage
drug use among employees, inmates, or students by not telling anyone who
or when they are to be tested in advance. However, critics claim that
random testing introduces a presumption of guilt, and is a violation of
privacy if the user is not actually intoxicated during working hours. In
addition, random testing is more likely to catch
cannabis users, since
THC metabolites have a longer duration in the body than those of
other drugs.
Post-incident drug testing
This is not a very commonly administered test compared to the other
two, but the financial ramifications of not testing employees
after an accident (or other incident) on the job makes this test
worthwhile for most businesses. The point of this test isn't necessarily
to cause the employee to lose his or her job, but rather to protect the
company from liability in the event that the individual is under the
influence at the time of the accident. If drugs or alcohol are detected
in any major quantity, the argument can be made in court that the
individual was intoxicated on the job, and for that reason, the company
should not be held liable for injuries sustained by the employee. This
argument, however, can only reasonably be made if blood or oral fluid /
saliva testing is used. Urine, hair, or sweat based testing can only
detect past drug use. Depending upon the facts of each case, this may
help a company avoid litigation completely or may do nothing to help
their case. DUI testing would also fall into this category. Another time
this type of test may be used is if an employee shows up for work
intoxicated, has alcohol on his or her breath, or appears to be impaired
in some other way. The goal of these tests is to protect the entity from
litigation, so they are only given on an as needed basis.
Legality and Ethics of Mandatory Drugs Testing
United Kingdom
The legal position of drug tests on the UK is not clear. A recent
study by the independent Inquiry into Drug Testing at Work found that
attempts by employers to force could be challenged as a violation of
privacy under the
Human Rights Act 1998 and Article 8 of the
European Convention of Human Rights. However, this may not extend to
industries where drug testing is a matter of safety rather than
productivity.
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