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DRUGS OF ABUSE
And Their Detection in Urine
Ed Uthman, MD [GEnie: E.UTHMAN]
Diplomate, American Board of Pathology
April, 1993
HOW DRUG SCREENS ARE PERFORMED
The aims of the drug screen are to detect the presence of frequently abused
drugs in the urine of human subjects. Drug screens are used for one of
three purposes:
1) medical purposes (e.g., to monitor a patient's progress in a medical
treatment program for a drug abuse problem the patient has
acknowledged),
2) legal purposes (e.g., to determine if a suspect had taken controlled
substances prior to some accident or crime), and
3) medicolegal purposes (e.g., in an employer's drug abuse program aimed at
both preventing drug-related accidents and crimes and identifying and
treating employees with drug abuse problems).
For medical purposes, laboratories often use simple, less-expensive
methods aimed at identifying specific drugs with which the patient has had
problems in the past. It is not expected that the results of such drug
tests will be used as evidence against the patient in court. If these
results are used as evidence, it is likely that defense testimony will
successfully impugn the evidence.
For legal and medicolegal purposes, more stringent testing is necessary
to obtain information that will successfully withstand technical criticism
in court. Therefore, drug screens done for these purposes often take a
two-tiered approach. First, there is a screening test done on the subject's
urine. This is usually a sensitive test that may have some discrepancies
in specificity (for instance, some popular over-the-counter cold medicines
may yield a positive amphetamine screen). Only if this test is positive for
one or more drugs is the second, more expensive test performed. Generally
courts will uphold testimony based on a drug test if positive results were
obtained on two separate tests based on different chemical methods.
AMPHETAMINES
Examples: amphetamine sulfate, dextroamphetamine (Dexedrine),
methamphetamine (Desoxyn, Methedrine).
Medical uses: Attention deficit disorder (hyperactivity) of childhood,
narcolepsy, obesity (occasionally and for limited period)
Effects attractive to abuser: Euphoria, increased ability to
concentrate, increased alertness, heightened ability to perform
intellectual and physical tasks, appetite suppression (for weight loss).
Adverse effects: Insomnia, restlessness, irritability, palpitations,
rapid heartbeat, sweating, dilation of pupils, confusion, psychosis,
convulsions, death.
How abused: Pills taken orally; solution injected intravenously;
occasionally snorted into the nose in granular form.
Typical urine detection cutoff level: 300 ng/mL
Period detectable after last dose: Up to 30 hours on low dose, 120 hours
on high dose.
Substances causing false positive results (on initial drug screen only):
decongestants (ephedrine [Vatronol, Efedron], phenylpropanolamine
[Propagest, Sucrets Decongestant Formula, Rhindecon]); "diet pills"
(phenmetrazine [Preludin], phentermine [Phentrol, Tora, Fastin, Obe-Nix,
Obephen, Obermine, Obestin, Parmine, Phentamine, Phentrol 2, Unifast,
Wilpowr, Adipex-P, Dapex-37.5, Ionamin, Phentrol], phenylpropanolamine
[Diadax, Prolamine, Control, Dex-A-Diet, Dexatrim-15, Unitrol, Maximum
Strength Acutrim, Appedrine]; blood vessel dilators (isoxuprine
[Vasodilan], nylidrin [Adrin, Arlidin]). Only confirmatory testing of the
urine will determine if these interfering drugs are present. It should be
noted that some of these drugs, such as phenmetrazine and phentermine,
while not technically amphetamines, have similar abuse potential and
similar adverse effects.
Phenylethylamine (a product of decomposing, unpreserved urine) may
produce false-positive screens in unrefrigerated, old specimens which have
not been treated with fluoride preservative.
BARBITURATES
Examples: Long acting- phenobarbital; intermediate-acting- amobarbital
(Amytal), butabarbital, talbutal; short-acting- secobarbital (Seconal),
pentobarbital (Nembutal).
Medical uses: Treatment of insomnia (short term only, and avoided
altogether by most physicians), long-term treatment of epilepsy
(phenobarbital), surgical anesthesia.
Effects attractive to abuser: Sedation, loss of inhibitions, induction
of sleep. Generally, the short-acting barbiturates have more abuse
potential than long-acting types.
Adverse effects: Agitation, confusion, nightmares, hallucinations,
lethargy, hangover, suppression of breathing reflexes, coma, death.
Physical dependence is well known, and withdrawal effects can be severe and
dangerous, even fatal.
How abused: Pills taken orally; solution injected intravenously.
Typical urine detection cutoff level: 300 ng/mL
Period detectable after last dose: long-acting 7 days, intermediate-acting
2-3 days; short-acting 1-2 days.
Substances causing false positive results: None reported.
METHADONE
Examples: Roxane, Dolophine
Medical uses: Treatment of opiate addicts in approved program
Effects attractive to abuser: Same as opiates (below)
Adverse effects: Same as opiates (below) but with lesser degree of physical
dependency (addiction)
How abused: Pills taken orally; solution injected intravenously.
Period detectable after last dose: 7.5-56 hours
Substances causing false positive results: doxylamine [Unisom Nighttime
Sleep Aid]. Presence of this substance would be ruled out by confirmatory
testing.
OPIATES
Examples: Morphine, heroin, codeine (as found in many prescription cough
medicines, such as Robitussin-AC, and pain medications, such as Tylenol
#3, Phenaphen #3 & #4, Empirin #3 & #4), oxycodone (Percodan),
hydromorphone (Dilaudid), hydrocodone (as in many prescription cough
medicines).
Medical uses: Relief of moderate to severe pain, treatment of persistent
cough (codeine), treatment of diarrhea.
>>> Continued to next message
* OLX 2.1 TD * ..What we got here is an ability to communicate..
___ Olms 1.60 [PSTB94B4]
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Msg#: 463 Date: 02-07-95 20:29
From: Dr_.dan@helix.eskimo.com Read: Yes Replied: No
To: All Mark:
Subj: drug tests 2/4
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net!eskimo!helix!Dr_.Dan
From: Dr_.Dan@helix.eskimo.com (Dr. Dan)
Date: 07 Feb 95 20:29:49 -0800
Newsgroups: alt.drugs
Subject: drug tests 2/4
Message-ID: <03e_9502072146@helix.eskinews.eskimo.com>
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>>> Continued from previous message
Effects attractive to abuser: Euphoria, sedation.
Adverse effects: Drowsiness, apathy, confusion, nausea, vomiting,
suppression of breathing reflexes, constricted pupils, physical addiction,
coma, death.
How abused: Pills taken orally; solution injected intravenously or
subcutaneously; occasionally snorted into the nose in granular form.
Typical urine detection cutoff level: 300 ng/mL
Period detectable after last dose: heroin, 1-4 days; meperidine, 4-24
hours; morphine, 84 hour minimum
Notes: This family of drugs undergoes extensive chemical changes due to
the normal detoxification processes of the body. Therefore, the drug
detected in the urine screen may not be the same as that originally taken
by the subject. For instance, both heroin and codeine are converted to
morphine before excretion in the urine.
Substances causing false positive results: none reported; however, foods
containing poppy seeds (the natural source of traditional opiate drugs)
will produce true positive results when screening the urine of an otherwise
innocent subject.
BENZODIAZEPINES
Examples: Diazepam (Valium), chlordiazepoxide (Librium), flurazepam
(Dalmane), oxazepam (Serax), lorazepam (Ativan), clonazepam (Clonopin).
Medical uses: Treatment of anxiety disorders, convulsions, and muscle
spasms.
Effects attractive to abuser: Euphoria, sedation, relief of anxiety,
induction of sleep.
Adverse effects: Drowsiness, apathy, fatigue, decreased activity level,
dizziness, fainting, impaired ability to concentrate on tasks,
disturbance of vision and hearing, physical addiction.
How abused: Pills taken orally.
Typical urine detection cutoff level: 300 ng/mL
Period detectable after last dose: around 2-4 days, but depending
greatly on dose. For instance, a single 10 mg PO dose of diazepam may not
ever be detected, but a 5 times daily dose of 10 mg will be detectable for
3-7 days.
Substances causing false positive results: none reported.
CANNABINOIDS
Examples: Marijuana, hashish, hash oil
Medical uses: Treatment of nausea and vomiting due to cancer chemotherapy.
Effects attractive to abuser: Euphoria, intensified sensual and
aesthetic perceptions.
Adverse effects: Paranoia, panic, impairment of memory and ability to
perform tasks, distorted perception of time, physical and psychological
dependence.
How abused: Smoked in cigarettes or pipe; occasionally eaten as
ingredient baked into confections.
Typical urine detection cutoff level: 100 ng/mL or 20 ng/mL (optional)
Period detectable after last dose: This is highly variable. A one joint
per week user has detectable levels of cannabinoids form 7 to 34 days,
while a heavy daily user may be detected from 6 to 81 days after last use.
Substances causing false positive results: none reported. A screen
detection cutoff level of 20 ng/mL, requested by some laboratory clients,
may produce false positives due to passive inhalation of marijuana smoke,
but this is controversial.
At the cutoff level of 100 ng/mL, persons exposed passively to the smoke
of others by virtue of being in the same room with abusers should be
negative on urine drug screen, although more sensitive chemical techniques
(such as gas chromatography/mass spectrometry, which has a sensitivity of
10 ng/mL) may demonstrate the drug in such an individual's urine.
COCAINE
Examples: Cocaine hydrochloride is the typical form used by abusers who
ingest the drug by snorting the granular form into the nose; it can also be
dissolved in water and injected intravenously. Cocaine base is available in
a waxy cake form ("rock" or "crack") which is vaporized with a torch and
the vapors inhaled through a tube.
Medical uses: Used almost exclusively by ear, nose and throat doctors to
produce local anesthesia and control blood loss during minor nasal
surgery.
Effects attractive to abuser: Euphoria, increased ability to
concentrate, increased alertness, heightened ability to perform
intellectual and physical tasks, sexual stimulation, heightened
sociability, enhanced self-confidence.
Adverse effects: Restlessness, nervousness, tremor, convulsions,
disturbances in heart rhythm, psychological dependence, myocardial
infarction, sudden death.
How abused: Snorted, injected, or smoked (see above).
Typical urine detection cutoff level: 300 ng/mL
Period detectable after last dose: 8-48 hours
Note: The laboratory detection of cocaine is performed by analyzing the
urine for the presence of benzoylecgonine, a substance produced by the
body's chemical detoxification of cocaine. Continuous conversion of cocaine
to the metabolite occurs in voided, standing urine specimens (even with
fluoridation and refrigeration) unless the specimen is kept at acid pH
(<5). This may give the appearance of a negative specimen "turning
positive" during storage, if the initial level of the metabolite was too
low to trigger the screen in the fresh specimen. In truth, the specimen was
positive all along, of course.
Substances causing false positive results: none reported; however, some
legal South American herbal teas may contain small amounts of coca leaf
extract, which may trigger a positive test in an "innocent" subject. Please
note that cocoa, cacao, and Coca Cola are all completely unrelated to coca,
which is the source of cocaine.
METHAQUALONE
Examples: Quaalude, Sopor
Medical uses: Once used as a sleeping pill/sedative, now methaqualone is
virtually never used for medical purposes.
Effects attractive to abuser: Same as that for barbiturates (see above)
Adverse effects: Same as that for barbiturates (see above)
How abused: Pills taken orally.
Typical urine detection cutoff level: 300 ng/mL
Period detectable after last dose: up to 90 hours, depending on dose
>>> Continued to next message
* OLX 2.1 TD * ..What we got here is an ability to communicate..
___ Olms 1.60 [PSTB94B4]
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Msg#: 464 Date: 02-07-95 20:29
From: Dr_.dan@helix.eskimo.com Read: Yes Replied: No
To: All Mark:
Subj: drug tests 3/4
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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net!eskimo!helix!Dr_.Dan
From: Dr_.Dan@helix.eskimo.com (Dr. Dan)
Date: 07 Feb 95 20:29:50 -0800
Newsgroups: alt.drugs
Subject: drug tests 3/4
Message-ID: <03f_9502072146@helix.eskinews.eskimo.com>
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>>> Continued from previous message
Substances causing false positive results: none reported.
PHENCYCLIDINE
Examples: PCP, "angel dust"
Medical uses: Veterinary tranquilizer; not used in human medicine.
Effects attractive to abuser: Hallucinogenic effects
Adverse effects: Lethargy, loss of co/rdination; unpredictable
psychosis, sometimes with criminally violent behavior; death.
How abused: Taken orally, smoked in cigarette (often mixed with
marijuana), injected intravenously as a solution, snorted into the nose in
granular form.
Typical urine detection cutoff level: 75 ng/mL
Period detectable after last dose: 5-10 days
Substances causing false positive results: Thioridazine (Mellaril), an
antipsychotic drug, has been reported to cause false positive results,
as has the insecticide parathion.
PROPOXYPHENE
Examples: Darvon, Dolene, Doxaphene, Profene 65
Medical uses: Relief of mild to moderate pain.
Effects attractive to abuser: Same as that for opiates (see above)
Adverse effects: Same as that for opiates (see above).
How abused: Pills taken orally; occasionally injected as solution made
by dissolving pills in water.
Period detectable after last dose: 1-3 days
Note: Propoxyphene is technically an opiate and is chemically closely
related to methadone. As a pain-relieving drug, it is two-thirds as potent
as codeine. Although considered something of a minor leaguer in the opiate
world, it is nevertheless a cause of many drug-related deaths (including
that of former football star John Matuszak) especially if used in
combination with alcohol and other drugs.
Substances causing false positive results: Methadone (see above) at
high, toxic concentrations may cause false positive results. Confirmation
testing will eliminate interference by this drug.
ALCOHOL (ETHANOL)
Examples: Beer, wine, distilled spirits
Medical uses: Rarely, if ever, used for medical purposes.
Effects attractive to abuser: Release of social inhibitions, euphoria,
sedation
Adverse effects: Same as that for barbiturates (see above). Also, use by
pregnant women, even in small ("social") amounts may have adverse effect
on the fetus.
How abused: Drunk in beverage
Period detectable after last dose: 8-10 hours
Note: Alcohol is the only drug of abuse (other than tobacco) that is
legal for all adults to use. Illegal use (as in driving while intoxicated)
is defined by the presence of a blood alcohol level of greater than 100
mg/dL (0.10% by volume) in Texas (lower in some other states). It is
impossible to determine if a subject is legally intoxicated by measurement
of the urine alcohol level.
A blood specimen must be collected for this determination to be made by
a clinical laboratory.
LIMITATIONS OF DRUG SCREENS
From a practical viewpoint it is impossible to determine in every case
that a given individual is impaired in the workplace due to drug abuse.
Just as in the case of alcohol, the use of drugs spans a wide spectrum of
behavior, from the occasional recreational user who assiduously avoids
coming to work under the influence, to the hard-core addict whose only
motivation is the acquisition of his or her next dose. Generally the
clinical laboratory is not able to distinguish these two types of
individuals. Such a distinction comes about only by careful evaluation by
professionals specially trained in the psychology and physiology of drug
abuse. The laboratory should be used only as a helpful tool for such
professionals.
Urine drug screens panels are set up to analyze urine for a variety of
drugs that are known to have high abuse potential and affect task
performance.
To rule out the presence of all drugs that may impair a worker's
performance is not generally allowable within the bounds of cost
containment. Certain drugs which are not usually picked up on routine drug
screens are noted below. If intoxication by any of the drugs listed below
is suspected, it is recommended that the client contact the B&A
pathologist, who will be glad to help determine a strategy as to how the
case should be most efficiently handled.
Methylphenidate (Ritalin), phentermine (Fastin, Parmine), phenmetrazine
(Preludin), phendimetrazine (Plegine), diethylpropion (Tenuate),
mazindol (Mazanor, Sanorex), benzphetamine (Didrex) and fenfluramine
(Pondimin) all have amphetamine-like effects and abuse potential. Some of
them, such as phentermine, benzphetamine, fenfluramine and diethylpropion,
may not be picked up on routine screens.
Methylenedioxyamphetamine (MDA, "Ecstasy") is has been popular in
Houston high schools. Although it is technically an amphetamine, it
requires a special analysis to be identified.
Lysergic acid diethylamide (LSD) is also chemically related to the
amphetamines, but it is much better known for its profound
hallucinogenic effects. Special analysis is available.
Meperidine (Demerol) and pentazocine (Talwin) have physiological effects
and abuse potential essentially identical to those of opiates. However,
since they are chemically dissimilar to morphine, they may not show up as
"opiates" on a routine screen. Special analysis is available.
Barbiturates which are not easily detected on drug screens include
amobarbital (Amytal), pentobarbital (Nembutal), and butethal. The detection
systems used to pick up barbiturates are optimized for secobarbital
(Seconal), which is probably the most important barbiturate in abusing
populations.
Flurazepam (Dalmane), a benzodiazepine used as a sleeping pill, is not
ordinarily picked up on benzodiazepine screens.
Glutethimide (Doriden), ethchlorvynol (Placidyl), meprobamate (Miltown,
Equanil), methyprylon (Noludar), and ethinamate (Valmid) are sedative
drugs that can produce dependence and impaired function. Although they may
have some effects similar to those of the barbiturates, they are chemically
unrelated and must be detected with special procedures.
Hydrocarbon solvents. These are inhaled by glue sniffers to produce a
euphoric effect. Although this seems to be less of a problem socially now
than in previous years, special analysis of hydrocarbons and chlorinated
hydrocarbons is available.
>>> Continued to next message
* OLX 2.1 TD * ..What we got here is an ability to communicate..
___ Olms 1.60 [PSTB94B4]
<EFBFBD> Area: alt.drugs <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Msg#: 465 Date: 02-07-95 20:29
From: Dr_.dan@helix.eskimo.com Read: Yes Replied: No
To: All Mark:
Subj: drug tests 4/4
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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skimo!helix!Dr_.Dan
From: Dr_.Dan@helix.eskimo.com (Dr. Dan)
Date: 07 Feb 95 20:29:51 -0800
Newsgroups: alt.drugs
Subject: drug tests 4/4
Message-ID: <040_9502072146@helix.eskinews.eskimo.com>
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>>> Continued from previous message
Ketamine (Ketalar), chemically related to phencyclidine (PCP), is used
as a general anesthetic but has been abused, often by health care workers.
It must be injected for effect. Analysis is available only through
specialized laboratories, and turnaround time is typically long.
Designer opiates. These, like meperidine, are synthetic analogues of
natural opiates. Accordingly, their chemical structure may be so alien to
that of natural opiates that they go completely undetected. These are
medically very significant drugs. For instance, 3-methylfentanyl ("China
white") is 3000 times as potent as morphine and has been responsible for
over 100 overdose deaths in California. Another, 1-methyl-4-
phenylpropionoxypiperidine (MPPP), may be contaminated with an unintended
byproduct (1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine, or MPTP) which
destroys the substantia nigra of the brain and produces permanent
parkinsonism.
Adulteration of urine samples with such substances as lemon juice,
vinegar, chlorine bleach, and NaCl has been used to successfully interfere
with detection of cannabinoids. Also, marked overhydration of the subject
(by quaffing large volumes of water) may so dilute the urine that the
concentration of the telltale metabolite falls below the detection
threshold of the screen.
A WORD ON TEST RELIABILITY
Published data indicate that a system of drug screening similar to that
used by most laboratories has a sensitivity of 76% and a specificity of
99%. This excellent specificity parameter means that of 100 persons who do
not use drugs, 99 would be expected to test negative by confirmation. This
is certainly an excellent specificity for any medical determination.
However, one should also be aware of another parameter, the predictive
value of a positive test. As applied to drug testing, this figure expresses
the probability that a subject that has tested positively has in fact used
the drug. Although a high specificity, such as 99%, optimizes the
predictive value, a more significant factor is the prevalence of drug use
in the population being tested. The more prevalent the usage of drugs in a
subject population, the greater the reliability of drug testing procedure.
Given the sensitivity and specificity values quoted above, the following
table indicates the predictive value for several levels of drug abuse
prevalence.
Percentage of tested population | Probability that a given
using drugs (the prevalence of | subject that tests positive
drug abuse) | has really taken the drug
| (the predictive value of a
| positive test)
______________________________________________________________________
0.1% | 7.1%
1.0% | 43.4%
10.0% | 89.4%
20.0% | 95.0%
50.0% | 98.7%
Therefore, in a population with a high incidence of drug use (200 per
thousand), the false positive rate on drug screens is only 5%, while in
a low-incidence population (1 per thousand) the false positive rate on
randomly screened individuals (i.e., those of whom there is no particular
suspicion of drug use) is expected to be a whopping 93%! For this reason,
it is my recommendation that drug screens not be applied on a random,
not-for-cause basis, except in situations where the prevalence of drug use
is known to be high (such as in substance abuse treatment programs).
DISTRIBUTION RESTRICTIONS: This monograph may be freely duplicated and
reformatted, as long as the informational content is not altered. It may
be freely distributed, if 1) the author is given credit, and 2) it is not
used as an aid for marketing or maintaining commercial laboratory accounts
without prior express written permission of the author
Copyright (C) 1989, 1993, Edward O. Uthman
CH OH
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* OLX 2.1 TD * ..What we got here is an ability to communicate..
___ Olms 1.60 [PSTB94B4]
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