False Positive Influencers

Toxicology Student Submissions September 2, 2016 Forensic Toxicology

Article overview: This article explains False Positive Influencers and the scientific, legal or practical evidence readers should understand.

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What can cause a false-positive toxicology result?

Forensic Toxicologist can Disprove False Positives Most of the population, including professional athletes, school teachers and even the President, will have to undergo a mandatory drug test at some point in their lives. Of this group of people, some will test positive for drugs they have not consumed due to certain false positive influencing substances. When this happens a forensic toxicologist may be employed to unequivocally prove whether or not the person has used illegal substances by analyzing the chemical content in their sample. Drug Testing – How It Goes Wrong The laws surrounding pre-employment and random workplace drug testing varies from state to state, however many employees in the federal or private sector are accustomed to the act of ‘urinating in a cup’. Urine drug tests usually screen for the presence of alcohol, amphetamines, benzodiazepines, marijuana, cocaine, PCP, and opioids (narcotics). However, the most common and quickest urine test, the immunoassay, does screen for all narcotics, and returns false-positives at a higher rate than the more expensive gas chromatography/mass spectrometry (GC/MS). GC/MS tests very rarely show false-positives, yet are not commonly used as drug screening tests due to the longer waiting period for results and the fact that these tests are more expensive than the immunoassays. Although using a combination of the two tests results in a very low potential to produce false-positives, there are still certain substances that can result in employees failing drug tests without having actually ingested any drugs. Cold and Flu Medication Nasal congestion is often caused by a dilation of the blood vessels in the sinuses, causing pressure and blockages in the nasal area. Over-the-counter medications known as decongestants alleviate the symptoms of a cold by constricting the blood vessels in a sick person’s nose, however many of these medications contain pseudoephedrine. Because pseudoephedrine is an artificial amphetamine, it is often used to make illegal drugs like crystal meth, and can show up as a false positive for illegal amphetamines. Ibuprofen and Other NSAIDS Nonsteroidal anti-inflammatory drugs (NSAIDS) are a group of over-the-counter drugs that have analgesic (pain-killing), antipyretic (fever-reducing) and anti-inflammatory properties. Although they are considered non-narcotic and therefore non-addictive, many of these drugs can show up in drug tests as false-positives for marijuana. Ibuprofen especially causes false-positives for marijuana, benzodiazepines and barbiturates, according to a review in the Mayo Clinic Proceedings. Poppy Seeds Organic opiates such as opium and codeine are derived from the seeds of the opium poppy, which are also used to flavor and decorate certain foods such as poppy seed breads or bagels. After the seeds are harvested they are thoroughly cleaned in order to removed any traces of opiates, however it is still possible for a person to test positive for opiates after simply having eaten foods that contain poppy seeds. Hemp Seeds and Oils Although hemp will not make anyone who ingests it experience a marijuana-like high, it does still contain minute traces of the psychoactive substance tetrahydrocannabinol (THC). Because hemp seeds contain beneficial fatty acids as well as high-quality protein, they are becoming more and more popular amongst the diet-conscious. Hemp seeds and oils derived from the seeds can be found in most health stores nowadays, however because they contain traces of THC persons who ingest any form of hemp may test positive for marijuana. Tonic Water Tonic water, also known as quinine water, is often consumed with alcohol but was originally used to combat malaria. If large quantities of tonic water are consumed before undergoing a drug test, the results may show a false positive for opiates. Remember that if you have undergone a drug test and tested positive for illegal substances that you know you have not consumed, you have the right to challenge this results. Do not hesitate to contact a forensic toxicologist to help you prove your innocence.

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