|Medications & Substances
Causing False Positives
|According to a report by the
Los Angeles Times News Service , a study of 161 prescription
and over the counter medications showed that 65 of them produced
false positive results in the most widely administered urine
Ronald Siegel, a psychopharmacologist at UCLA said 'The widespread testing
and reliance on tell-tale traces of drugs in the urine is simply a panic
reaction invoked because the normal techniques for controlling drug use
haven't worked very well. The next epidemic will be testing abuse."
Byrd Labs has in its possession an internal
document from the Syva Company , makers of the widely used EMIT test.
This document, leaked by a disillusioned company employee, lists more than
250 over-the-counter medications and prescription drugs that can cause
false positives. For a complete list, please check the back of this book.
Among the items reported
as causing false positive test results are:
|• Pain relievers such as Advil,
Nuprin, Motrin and menstrual cramp medications like Midol and
Trendar. All drugs containing the widely used pain reliever
Ibuprofen, are known to cause. positive samples for Marijuana.
Non steroidal anti inflammatory such as Naproxyn have cross
reacted in blind tests. These are often prescribed for runners,
sports injuries to joints, and those suffering from arthritis.
Syva labs has recently reworked its Cannabanoid test and claims to have
eliminated this problem. But a Science magazine article (July 8, 1988)
lists Ibuprofen as a cross reactive. Under the new government guidelines
THC testing levels will be reduced to 50 nanograms. Many more THC false
positives can be expected in 1994.
• Dristan Nasal Spray, Neosynephren, Vicks Nasal
Spray, Sudafed, etc. and others containing ephedrine or phenypropanolamine.
Over the counter appetite suppressants which contain propanolamine.
Most common nasal decongestants can cause a positive reading for
Amphetamines. As the cross reactive list suggests at the back of
this booklet, amphetamine false positives are the most common. Recent
articles in the Journal of Clinical Chemistry , Vol. 38 No. 12 1992
and Vol. 39 No. 3 1993 warn that medications containing chloropromazine,
fluspirilene, and others may yield a positive when tested for amphetamines.
• Vicks Formula 44M containing Dextromethorphan,
and Primatene-M containing perylamine as well as the pain reliever
Demerol, and prescription anti-depressant Elavil test positive for
opiates up to three days. Even Quinine water can also cause a positive
reading for opiates.
•Poppy Seeds such as on the Burger King roll, on
a bagel from your favorite deli, etc. The journal of Clinical Chemistry
Vol. 33 No. 6, 1987 reports: "the quantities of poppy seed ingested
in this study (25 and 40 g) may be expected to be contained in one
or two servings of poppy seed cake. therefore, poppy seeds represent
a potentially serious source of falsely positive results in testing
opiate abuse." Clinical Chemistry goes on to conclude: Not only is
it difficult to distinguish heroin or morphine abuse from codeine,
but dietary poppy seeds can give a strong positive result for urinary
opiate of several days duration that is confirmed by GC/MS analysis".
• Nyquil Nighttime Cold Medicine will test positive
for Methadone up to two days.
• Antibiotics. Certain newly developed antibiotics
have cause positive samples urine tests. Ampicillin is suspect. Amoxicillin
has caused positives for cocaine.
•Diazepam found in Valium, tests positive for PCP
as well as the ingredient in some cough medicines, Dextromethorophan.
• Your own enzymes. A small fraction of the population
have excrete large amounts of certain enzymes in their urine which
can produce a positive drug test. Dr. John Morgan of the Dept. of
Pharmacology of New York City Univ. write: "A false positive test
could occur in some individuals because they excrete unusually large
amounts of endogenous lysozyme or malate dehydrogenase." Dr. Morgan
judges that natural enzyme interference may run as high as 10% of
• Black Skin. This is not a joke! Those of African
origin, certain Orientals, or pacific Islanders might test positive
for marijuana. Dr. James Woodford, a toxicologist associated with
Emory University labs hypothesized pigment melanin which protects
the skin from the sun, approximates the molecular structure of the
THC metabolite to cross react on the marijuana urine test. Dark skinned
Caucasians such as those from the sub-continent of India could also
read positive on the marijuana test. The body eliminates some melanin
in a dark person's urine sample.
• Passive marijuana inhalation. If you attend a
rock concert or ride in a car where marijuana is smoked nearby, even
if you do not partake, the second hand marijuana that you might inhale
can give your test a positive result for several days.