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Pros and
Cons of the Various Drug Testing Methods
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Urine
Results of a urine test show the presence or absence of
specific drugs or drug metabolites in the urine. Metabolites are drug residues
that remain in the system for some time after the effects of the drug have
worn off. A positive urine test does not necessarily mean the subject was
under the influence of drugs at the time of the test. Rather, it detects and
measures use of a particular drug within the previous few days.
Hair
Analysis of hair may provide a much longer testing window for the
presence of drugs and drug metabolites, giving a more complete drug-use
history that goes back as far as 90 days. Like urine testing, hair testing
does not provide evidence of current impairment, only past use of a specific
drug. Hair testing cannot be used to detect alcohol.
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TYPES
OF TESTS |
PROS |
CONS |
WINDOW
OF DETECTION |
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URINE |
Highest assurance of reliable results.
Least expensive.
Most flexibility in testing different drugs, including alcohol and
nicotine.
Most likely of all drug-testing methods to withstand legal challenge.
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Specimen can be adulterated, substituted, or diluted.
Limited window of detection.
Test sometimes viewed as invasive or embarrassing.
Biological hazard for specimen handling and shipping to lab.
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Typically 1 to 5 days.
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HAIR |
Longer window of detection.
Greater stability (does not deteriorate).
Can measure chronic drug use.
Convenient shipping and storage (no need to refrigerate).
Collection procedure not considered invasive or embarrassing.
More difficult to adulterate than urine.
Detects alcohol/cocaine combination use.
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More expensive.
Test usually limited to basic 5-drug panel.
Cannot detect alcohol use.
Will not detect very recent drug use (1 to 7 days prior to test).
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Depends on the length of hair in the sample. Hair grows about a
half-inch per month, so a 1╫-inch specimen would show a 3-month history.
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ORAL
FLUIDS |
Sample obtained under direct observation.
Minimal risk of tampering.
Non-invasive.
Samples can be collected easily in virtually any environment.
Can detect alcohol use.
Reflects recent drug use.
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Drugs and drug metabolites do not remain in oral fluids as long as they
do in urine.
Less efficient than other testing methods in detecting marijuana use.
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Approximately 10 to 24 hours.
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SWEAT
PATCH |
Non-invasive.
Variable removal date (generally 1 to 7 days).
Quick application and removal.
Longer window of detection than urine.
No sample substitution possible.
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Limited number of labs able to process results.
People with skin eruptions, excessive hair, or cuts and abrasions cannot
wear the patch.
Passive exposure to drugs may contaminate patch and affect results.
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Patch retains evidence of drug use for at least 7 days, and can detect
even low levels of drugs 2 to 5 hours after last use.
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Sweat Patch
Another type of drug test consists of a skin patch
that measures drugs and drug metabolites in perspiration. The patch, which
looks like a large adhesive bandage, is applied to the skin and worn for some
length of time. A gas-permeable membrane on the patch protects the tested area
from dirt and other contaminants. The sweat patch is sometimes used in the
criminal justice system to monitor drug use by parolees and probationers, but
so far it has not been widely used in workplaces or schools.
Oral Fluids
Traces of drugs, drug metabolites, and alcohol can be detected in oral
fluids, the generic term for saliva and other material collected from the
mouth. Oral fluids are easy to collect—a swab of the inner cheek is the most
common way. They are harder to adulterate or substitute, and collection is
less invasive than with urine or hair testing. Because drugs and drug
metabolites do not remain in oral fluids as long as they do in urine, this
method shows more promise in determining current use and impairment.
Breath Alcohol
Unlike urine tests, breath-alcohol tests do detect and measure current
alcohol levels. The subject blows into a breath-alcohol test device, and the
results are given as a number, known as the Blood Alcohol Concentration, which
shows the level of alcohol in the blood at the time the test was taken. In the
U.S. Department of Transportation regulations, an alcohol level of 0.04 is
high enough to stop someone from performing a safety-sensitive task for that
day.
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