Why Drug testing is Bad for your Employment

The majority of companies mistakenly believe that drug tests are scientific and objective. The fact is that drug testing approaches are open to abuse. Problems related to drug testing can impinge upon your freedoms and even mean that you lose your job. The first reason for this is that they frequently produce inaccurate results! It may be that you return a positive drug test result even if you haven't taken any drugs. Similarly, the positive result to a drug test should not be used as evidence that an employee was impaired at the time of the test, even though a lot of employers will make this connection automatically. Regardless of these facts, an employer may be inclined to act upon a positive drug test result to humiliate, discipline or even terminate the employment of one of their workers. These are the main reasons why drug testing is bad for the work environment!

Validity of Drug tests

Drug testing methods are far from perfect. In a well-known study that proved this point, the Center for Disease Control (CDC) delivered urine samples to 13 different laboratories that were engaged to conduct drug tests for methadone programs. These samples contained specific amounts of amphetamines, methadone, barbiturates, cocaine, morphine and codeine. The laboratories were not informed of the study. The CDC found error rates in the test reports of as much as 94% for the false negative results (where the labs were not able to find drugs that were present) and 66% in the false positive results (where the labs reported drugs that weren't actually present). Since this study the standards of the laboratories have improved thanks to better methodology which has made them more reliable. However, there are still problems.

Numerous Mistakes

Mistakes in the drug-testing process can be made at many times during the process, whether it's during the collection, the identification or the reporting phases. A "false positive" result refers to the situation where a positive result is recorded for a sample that is free of drugs. A "false negative" result refers to the situation where a sample that does in fact contain drugs is found by the test to be drug free. The reasons behind false positive results can include lazy lab work such as a technician contaminating a sample or reading the results incorrectly,

The Director of the Haight Ashbury Free Clinic, David Smith, had this to see about the CDC study: "in many cases the labs would have done a better job if they had poured the urine down the drain and flipped a coin." An opposing argument was made by the Quality Assurance Manager from PharmChem, Bob Fogerson who contended that "it is not valid to conclude drug testing cannot be done accurately just because it has not been done accurately." In the meantime, you and other regular employees are being treated as guinea pigs while accurate testing methods are developed!

The many problems inherent in drug testing (such as poor laboratories, faulty results, legal action and human error) became obvious immediately after the mass-screening of military personnel. The American Civil Liberties Union has estimated that up to 30,000 (or 30%) of the Army and Air Force personnel who tested positive to their screening drug-tests may be eligible to have the charges brought against them dropped as a result of mistakes in the testing process. The screenings conducted by the Navy were similarly problematic. 2,000 of the 6,000 tests ordered by the Navy were unable to be "scientifically substantiated as positive". The validity of a further 2,000 of these results was found to be questionable due to missing documentation.

False Positives � Opiates

A positive result for opiates is one of the hardest tasks for organizations responsible for analyzing urine drug tests, such as Medical Review Officers (MROs). Around 70% of the positive opiates results returned for employees of the Department of Transportation (DOT) were caused by poppy seeds. Consuming poppy seeds, prescription drugs and some legal over-the-counter pharmaceuticals can return positive opiates results. The correct interpretation of urine sample tests for opiates is a complicated process.

A report from Toxnet Laboratory contends that poppy seeds found in regular bakery goods like bagels can produce a positive result for opiates (morphine) in levels below 3,000 ng/ml. Ingesting poppy seeds may also produce positive results for codeine. While morphine is a metabolite of the codeine drug, when found in poppy seeds codeine comes from the actual seeds rather than being a metabolite. A high level of codeine (that is, higher than the level of morphine) generally suggests the ingestion of codeine.

The false positives for opiates disrupted the lives of thousands of employees of DOT. This prompted the government to finally change the Mandatory Guidelines for Federal Workplace Drug testing Programs. This amendment involved raising the cut-off level (from 300 to 2,000 ng/ml), as well as the confirmation levels required for opiate testing. These amendments came into force in May 1998.

The potential inaccuracies resulting from poppy seed consumption and opiate drug testing can be seen in the following report from Toxnet Laboratory:

"A preplacement urine screened positive for opiates by radioimmunoassay and EMIT. Gas chromatography / mass spectrometry (GC/MS) identified 487 ng/ml morphine. The individual denied opioid abuse. Inquiry by the examining medical center revealed a diet consisting of a Burger King hamburger the night before the specimen was taken and a breakfast, apparently usual, of two bagels from the university snack bar. The individual appeared to be quite normal. TOXNET LABORATORY obtained a bagel from the snack bar. Pulverization of a few poppy seeds used as decoration on the bagel resulted in positive immunoassay (RIA and EMIT) responses. A TOXNET LABORATORY toxicologist volunteered to eat the bagel and collect urine post-dose. The first urine, three hours post dose, resulted in an opiate level, as determined by Roche radioimmunoassay (RIA), of 250 ng/ml. By six hours post dose the level had dropped to about 60 ng/ml and was negative (sensitivity 30 ng/ml) by 12 hours post dose.

TOXNET LABORATORY obtained a bottle of Schillings poppy seeds, imported from the Netherlands, from a local market and had the laboratory volunteer eat three teaspoons, six grams, of the seeds. The first urine was collected six hours post dose and had the highest opiate level, approximately 1200 ng/ml as determined by the Roche radioimmunoassay (RIA). Levels twelve hours post dose dropped to about 250 ng/ml, and the urine was negative by twenty four hours post dose (sensitivity 30 ng/ml)."

Hemp Seed Foods

Tests conducted by Toxnet Laboratory also proved the cookies containing cannabis sativa seed (also commonly referred to as hemp seed) can result in a urine sample returning a positive result for cannabis. Despite the fact that wild variations of hemp cannabis contain very low levels of THC, these are enough to make a urine sample test positive after the seeds are ingested. Similar to poppy seeds, the quantity of the drug contained in the seeds is determined by their genetic origin. When hemp is raised for fiber it will contain a lot less THC than hemp strains that have been bred specifically for having high levels of psychoactive THC.

Toxnet tested urine samples taken from people who had recently eaten hemp cookies made by the Hungry Bear Hemp Food company. The particular cookies involved were called "Seedy Sweeties with Sunflower Seeds" and "Seedy Sweeties with Nuts". Three Toxnet volunteers gave urine samples before ingestion of the cookies to serve as the baseline, and then gave post-dose urine samples after eating 1 or 2 of the bars which each weighed 42.5 grams.

All three participants returned positive results. They screened over 50 ng/ml and 15 ng/ml for THC from the urine samples taken after they had eaten the cookies containing hemp seeds. Ingesting these bars orally resulted in a positive urine test within 4 hours of consumption, and for one participant the positive result lasted 48 hours from the cutoff. The peak levels of urinary excretion took place around 8 hours after the cookies were eaten.

Human Error

Many errors in drug testing are caused by untrained personnel, poor management, a break in the chain of possession of the samples, poorly maintained equipment and poorly executed reports, rather than problems with the actual tests. In some cases, the glassware used in the tests has been contaminated by samples that are positive for drugs and this can cause the false positive rate to climb by 3-5%.

Drug test manufacturers argue that the equipment used in the tests are between 95 and 99% accurate for detecting drug traces in urine samples. These rates apply only when the equipment is being operated by lab technicians employed by the test manufacturers who are being closely supervised. The accuracy rate for gas chromatography / mass spectrometry test is almost a perfect 100% according to manufacturers. However, these high rates of accuracy only apply when the tests are being administered by highly proficient and diligent lab technicians. In reality, these perfect conditions rarely occur. The drug testing equipment is frequently leased by the manufacturers to private hospitals and laboratories. The quality of the work undertaken in these drug testing labs is then monitored by the American Association of Clinical Chemistry (AAC), the American Association of Bioanalysts (AAB), and the College of American Pathologists (CAP).

The biggest problem is that the drug testing equipment can only ever be as reliable as its operators. If the lab technicians are tired, busy or simply incompetent, there are numerous ways that they can misuse the equipment. The consequences of this are false positive results and other mistakes.

The Need for Regulation

Dr David Smith from the Haight Ashbury Free Clinic spoke at the California State Senate Hearing that was evaluating the increased need for regulations in drug testing labs. He said that "in a random or mass testing, without probable cause, error is inevitable." In a typical situation, companies will chose to use the cheapest tests for screening. These tests only return a yes or no result and they always involve the potential for error. Samples are regularly collected by unqualified clerks which can also increase the risk of errors in a mass screening situation. Smith also argued that there is often a lack of information available for employers administering a screening. The lab technicians also often don't fully understand how the test works or how the data should be interpreted.

The main reasons behind errors in drug tests include:

  • Faulty lab procedures
  • Samples being mixed up
  • Paperwork being confused, damaged or lost
  • The passive inhalation of a drug
  • Cross-reaction with a legal drug
  • Samples being tampered with
  • Other unknown factors

False Positive Result

A false positive result occurs with a positive result is returned on a sample that is free of any traces of drugs. The reasons for false positives include problems with the methodology or contamination of the equipment. When drug tests take place, it is quite common for untrained personnel to be responsible for collected the samples onsite.

Having a high rate of false positives isn't really that important when the tests are being conducted for research purposes or as part of a drug treatment program or some other situation where no one is likely to be punished. When the tests occur as part of a pre-employment, promotion, job-fitness or probationary process however, having a urine sample that returns a positive result can have serious social and personal consequences. The consequences of this result, particular as it related to your employment, can be disastrous.

When a positive result is returned as part of an initial or screening test, it should always be confirmed. The confirmatory test should use a different methodology from the initial test. For example, it would be appropriate to use a chromatography test in order to confirm the results of an initial immunoassay test, because the methodologies involved are sufficiently different. On the other hand, RIA and EMIT methods should never be relied upon to confirm the results of a prior immunoassay test. It is OK to use the TLC method to confirm the results of an RIA test because TLC uses the chromatography methodology. When it comes to using TLC however, there are other issues to consider. TLC is generally used as a screening test and it is less accurate than a GC/MS or GC test. Where the confirmation of a positive drug test is likely to have a large impact on your life, you will obviously want the test used to be as accurate as possible. This means using the GC/MS method, and even testing a blood sample rather than just urine. This is particularly important when the tests are being conducted in response to an accident. The unfortunate reality however, is that many employers completely disregard these rules.


Allen and Stiles conducted a large study into cross-reactivity. This involved testing 161 prescription and other legitimate over-the-counter drugs using EMIT-d.a.u. screening tests. The drugs were tested for amphetamines, barbiturates, opiates, methadone, benzodiazepines, cocaine and propoxyphene. Of the 161 drugs tested, 65 had some degree of cross-reactivity. Some even had values higher than the cut-off. It was fortunate that the majority of these positive results involved concentration levels that would not be possible in a human urine sample and therefore did not pose any serious problem. This should be somewhat comforting, however it still goes to prove the consuming a legal prescription or other medication may result in testing positive to a drug test.

Some examples of medications that interfere in drug tests include Appedrine diet pills which can produce a positive result in an amphetamine drug test and Ibuprofen (contained in Advil and Nuprin) which can produce a positive result in a marijuana test. Around 150 medications that can be legally purchased over-the-counter have been found to cause positive results in tests for amphetamines and methedrines. These false positive scenarios are particularly common when the medications involved contain a synthetic compound such as phylpropanolamine. It has also been argued that the EMIT cocaine drug test can produce a false positive result if the subject had drunk a large amount of test prior to the test. Ingesting an anti-histamine may also result in a false positive result to a PCP test.

The manufacturers of the EMIT and the Abuscreen drug testing methods, Syva and Roche, say that they tell laboratories that their tests are designed to locate any broad classes of drug substances in a urine sample. This is known as "class assays" and it is especially applicable when it comes to opiates and amphetamines. For instance, when a sample is screened for heroin, the test will look for any substance that has a similar structure to morphine as this is the most basic type of opiate molecule. One substance that has a similar structure is dextromethorphan. This is a regular cough syrup component that can be found in many medicines such as Nyquil, Comtrex, Benylin and Peda-care. Both EMIT and Abuscreen methods of drug testing will return positive results for amphetamines if the urine sample contains phenylpropanolamine. This is a decongestant that can be found in many different popular medications (such as Alka-Seltzer Plus) and diet remedies (such as Dietac and Dexatrim).

The following table, initially prepared by Allen & Stiles, depicts the cross-reactivity levels of different products with EMIT.

Cross-Reactivity with EMIT at ? 100 mcg/ml
Generic Name Brand Name Cross-Reactivity
Amitriptyline HCI Elavil Methadone
Carisoprodol Soma Methadone
Clindinium bromide Quarzan Benzodiazepine
Cloxacillin Na Tegopen Benzodiazepine
Diphenhydramine HCI Benadry Methadone
Imipramine HCI Tofranil Methadone
Isoxuprine HCI Vasodilan Amphetamine
Orphenadrine citrate Norflex Methadone
Perphenazine Trilafon Benzodiazepine
Promethazine HCI Phenergan Methadone and Opiate
Thiethylperzine maleate Torecan Methadone
Tripelennamine HCI Pyribenzamine Benzodiazepine and Methadone

The research conducted by Syva found that cross-reactivity occurred with the EMIT and Abuscreen tests between ephedrine and amphetamines. Ephedrine is contained in many medicines that can legally be purchased over-the-counter.

The above table demonstrates the many ways in which cross-reactivity occurs with over-the-counter products when conducting EMIT tests. This is a serious concern as these products are in common use for a variety of regular conditions. For example, if you take a pharmacy medication for menstrual cramps you may find that your drug test results come back positive and you are put into the position of proving that you don't take drugs. Similarly, if you take Naproxym or a similar product to treat arthritis or another injury, you may return a positive drug test for steroids. You may even test positive for amphetamines if you are simply taking a nasal decongestant to treat cold symptoms as these products typically contain phenypropanolamine or ephedrine. Using Vick Formula 44M or having a poppy seed bagel for lunch may also result in a drug test coming back as positive for opiates. Taking an amoxicillin antibiotic may mean that your test is positive for cocaine. This is pretty scary stuff!

These common false positives confirm that honest people who have never taken drugs can get positive results to a drug test. When this happens, the person is automatically treated as a drug taker. The problem of cross-reactivity in drug testing is yet to be solved and many companies still don't understand how it works. Furthermore, you can still have a positive result even if you don't take any drugs (legal or illegal) thanks to processing errors, mistakes by lab technicians, and cross-reactivity. Returning a positive test result, regardless of your actual guilt or innocence, may mean that you lose your job.

This is why you need to be smart, well informed and proactive. With a little preparation you can make sure that you pass drug tests! Further information about what you can do to get prepared is available from mbdetox.com.