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 inflammatories 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 Cannabinoid test and claims to have eliminated this problem. But a Science magazine article (July 8, 1988) lists Ibuprofen as 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 pnenypropanolamine. 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 the ones 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 tests positive for PCP as well as the ingredient in some cough medicines, Dextromethorophan.

Your own enzymes. A small fraction of the population 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 University writes: "A false positive test could occur in some individuals because they excrete unusually large amounts of endogenons lysozyme or malate dehydrogenase." Dr. Morgan judges that natural enzyme interference may run as high as 10% of positive samples.

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 the 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 subcontinent of India could also read positive on marijuana tests. 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 may give your test a positive result for several days.