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Drug Test and False Positive

 According to news broadcast from the L. A. Times New Service, a study of 161 medicine drugs and OTC medications showed that 65 of them could formed false positive drug testing results in the commonly administered drug testing procedure – urine drug screening. 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." At this time there are over 250 OTC medications and prescription drugs can produce false 

positives drug testing result.

Drug Test Name Substances or Conditions which can 
cause drug testing false positives
Marijuana Drug Test • Dronabinol (Marinol)
• Ibuprofen; (Advil, Nuprin, Motrin, Excedrin IB etc)
• Ketoprofen (Orudis KT)
• Kidney infection (Kidney disease, diabetes) 
Liver Disease
• Naproxen (Aleve)
• Promethazine (Phenergan, Promethegan)
• Riboflavin (B2, Hempseed Oil)
Opiates Drug Test • Poppy Seeds
• Tylenol with codeine
• Most prescription pain medications
• Cough suppressants with Dextromethorphan 
(DXM)
• Nyquil
• Kidney infection, Kidney Disease
• Diabetes, Liver Disease
Amphetamines
Drug Test
• Ephedrine, pseudoephedrine, 
propylephedrine, phenylephrine, or 
desoxyephedrine (Nyquil, Contact, Sudafed, 
Allerest, Tavist-D, Dimetapp, etc)
• Phenegan-D, Robitussin Cold and Flu, Vicks 
Nyquil
• Over-the-counter diet aids with 
phenylpropanolamine (Dexatrim, Accutrim)
• Over-the-counter nasal sprays (Vicks inhaler, 
Afrin)
• Asthma medications (Marax, Bronkaid tablets, 
Primatine Tablets)
• Prescription medications
• (Amfepramone, Cathne, Etafediabe, Morazone, 
phendimetrazine, phenmetrazine, 
benzphetamine, fenfluramine, dexfenfluramine,
dexdenfluramine,Redux, mephentermine, 
Mesocarb, methoxyphenamine, phentermine,
amineptine, Pholedrine, 
hydroymethamphetamine, Dexedrine, 
amifepramone, clobenzorex,fenproyorex, 
mefenorex, fenelylline, Didrex, 
dextroamphetamine, methphenidate, Ritalin,
pemoline, Cylert, selegiline, Deprenyl, Eldepryl, 
Famprofazone)
• Kidney infection
• kidney disease
• Liver disease
• Diabetes
Ecstasy Drug Test • Ephedrine, pseudoephedrine, 
propylephedrine, phenylephrine, or 
desoxyephedrine (Nyquil, Contact, Sudafed, 
Allerest, Tavist-D, Dimetapp, etc)
• Phenegan-D, Robitussin Cold and Flu, Vicks 
Nyquil
• Over-the-counter diet aids with 
phenylpropanolamine (Dexatrim, Accutrim)
• Over-the-counter nasal sprays (Vicks inhaler, 
Afrin)
• Asthma medications (Marax, Bronkaid tablets, 
Primatine Tablets)
• Prescription medications (Amfepramone, 
Cathne, Etafediabe, Morazone,phendimetrazine, 
phenmetrazine, benzphetamine, fenfluramine, 
dexfenfluramine, dexdenfluramine,Redux, 
mephentermine, Mesocarb, methoxyphenamine, 
phentermine, amineptine, Pholedrine, 
hydroymethamphetamine, Dexedrine, 
amifepramone, clobenzorex, fenproyorex, 
mefenorex, fenelylline, Didrex, 
dextroamphetamine, methphenidate, Ritalin, 
pemoline, Cylert, selegiline, Deprenyl, Eldepryl, 
Famprofazone)
Eldepryl, Famprofazone)
pemoline, Cylert, selegiline, Deprenyl, Eldepryl, 
Famprofazone)
• Kidney infection
• kidney disease
• Liver disease
• Diabetes
Cocaine Drug Test • Kidney infection (kidney disease)
• Liver infection (liver disease)
• Diabetes
• Amoxicillin, tonic water
Benzodiazepine
Drug Test
• Most prescription sleeping pills and anti-
anxiety medication
Barbiturate Drug Test • Fiorinol
• Donnatol
• Some sleeping pills
• Antiasthmatic preparations that contain 
phenobarbitol
• Dilantin
LSD Drug Test • Migraine medications
• Ergostat
• Cafergot
• Wigraine
• Imitrex
• Hydergine
• Bromocription
• Methysergiside
• Lisuride
• Lysergol
• Artane
• Triprolidine
• Amitriptyline (Elavil)
• Dicyclomine (Bentyl)
• Antinausea Medications that contain 
Promethazine: Phenergan, Promethegan


Are you positive the drug test result is realy positive? - False positive drug testing of employees and high school students.

In the complex world of drug testing, HR professionals need to know some basics.

When we stopped asking questions in science class as the subject got too complicated, we were not very different from our peers. After all, since we weren't planning to do laboratory research, we'd never need to understand the details, or would we?

Given the complexity of workplace drug testing, it's easy to understand why we leave the science to the experts. But, since recent estimates show more than 90 percent of Fortune 1,000 companies have workplace drug-testing programs, how much should we understand about testing? Should we take the laboratory's word that their methods and technology are the most accurate available? Just how accurate is drug testing anyway?

Here is a layman's overview of just what happens to urine samples, and some of the issues that affect the choice of a drug-testing laboratory.

The ABCS of acronyms

Because workplace drug testing has an impact on both public- and private-sector employees, it's important to understand what regulations exist to ensure accurate test results. Based on presidential mandate, all federal workers (and contractors of the federal government) tested for drugs must have their samples analyzed at a federally certified drug laboratory. This federal certification program is conducted by the National Institute on Drug Abuse (NIDA), an agency of the U.S. Department of Health and Human Services (HHS).

Twelve states have also instituted certification programs requiring that state employees be tested in state-certified labs. In some states (Minnesota is one), private employers with drug-testing programs must use certified laboratories. However, most private-sector test samples are not regulated by the state or federal government. Choosing a test site is the responsibility of the corporate program administrator.

Fortunately, most laboratories without state or federal certification police themselves by participating in private certification programs. These programs test a laboratory's proficiency and provide a kind of "Good Housekeeping" seal of approval. One such private program is administered by the College of American Pathologists (CAP). Among the private programs, CAP, which conducts the Forensic Urine Drug Testing certification program, is a widely known and respected endorsement. Though private business testing is currently not subject to federal regulation, most legal advisors counsel private business to choose a certified laboratory.

Aside from federal workers, trucking companies, airlines, and other transportation industries with federal contracts have to meet drug-testing guidelines set by the Department of Transportation. The Nuclear Regulatory Commission also has its own set of guidelines for testing employees who are included under the federal program.

Step by step

Drug testing is based on three fundamental processes: sample collection, preliminary screening and confirmation testing.

The first step in testing - sample collection - is critical. Subjects typically provide urine samples, which are commonly collected at a company's medical clinic or at an offsite collection center. Because there are many ways urine samples can be adulterated, the HHS has established specific guidelines to ensure the identity and protect the integrity of samples. The guidelines require a secure location that allows individual privacy. Persons giving samples must show photo identification and are asked to sign a statement verifying that the sample they provide is, in fact, their own.

To ensure the sample is authentic, its temperature is measured. If the temperature is outside an acceptable range, another sample may be collected under direct observation by a collection site official of the same gender. Although permitted by HHS guidelines, this practice is not recommended by many legal counselors due to potential invasion-of-privacy litigation. Coats, purses, and other unnecessary outer garments cannot be taken into the stall in order to deter people from bringing in substitute urine samples or other agents, which may be added to their sample to dilute or otherwise affect it. Bluing agents are also commonly added to the toilet tank to prevent sample dilution.

The samples are sealed, labeled and dated by the collection site official and initialed by the person providing the sample. This process initiates a chain of custody. Chain-of-custody documentation provides a legal record of the sample's history and travel through the drug-testing process. Samples are then transported to the laboratory.

Which drugs are detectable?

Almost universally, workplace drug testing involves targeted drug analysis. That means a laboratory will test for a specific set of drugs and/or their metabolites. This means drugs that are present in the urine but outside the targeted list will not be detected. NIDA has focused federal testing on five drug classes. These classes include a total of seven drugs, some of which are not the parent drug, but rather, a metabolite. Included in the seven are the marijuana metabolite, he cocaine metabolite, the opiates (morphine and codeine), phencyclidine, and the amphetamines (amphetamine and methamphetamine).

In other words, although a company requests a cocaine test, a lab will test for cocaine's primary metabolite called benzoylecgonine. Since the body converts cocaine to benzoylecgonine, it is present in the urine in much higher concentrations than the parent drug cocaine, providing a longer window for detecting drug use.

NIDA has established cutoff concentration levels that define the sample as either positive or negative to help standardize laboratory performance. If the lab detects the targeted drug below the cutoff, the test is reported as negative. Though considered negative by the administrative cutoff, the presence of drugs, though small in amount, may still indicate a drug user. For this reason, many nonfederal testing programs request lower cutoff levels. This may not be warranted in the case of the opiates; when ingested, poppy seeds (which actually contain morphine) can be detected as a positive.

Laboratories can and will offer different packages to test for more drugs and/or the same drugs at lower levels. In fact, in some states, these drugs must be included in state drug-testing programs. The barbiturates (amobarbital, secobarbital, etc.), the benzodiazepines diazepam or Valium, and oxazepam or Serax), LSD, methaqualone (quaaludes), propoxyphene (Darvon) may all be included in a drug-testing program, although they are not mandated by federal testing guidelines.

In the lab

Considering that high-volume laboratories test as many as 3,000 samples per day, the first step in the analytical process is designed to eliminate, in the most efficient and inexpensive manner possible, samples that have no targeted drugs present.

This step, known as screening, uses an immunological test to detect drug classes. The test works like this: Antibodies that are tailored to react with specific drugs are mixed with a small quantity of the test subject's urine sample. In most of these tests, when drugs are present, the antibody reagent inside a testing tube creates a reaction which is read by an automated analyzer.

It is difficult to put a number on the accuracy of immunological tests. Some claim put the number in the 94 percent to 95 percent accuracy range, but many factors influence those figures. Included in these factors are the level of detection (how little drug can be detected in the sample) and the ability of the screen to identify only the specific drugs of interest. Of course, the ability of technicians to correctly handle the sample and administer the test is critical and not a factor that has been carefully studied.

The problem with immunological screening is that compounds other than the targeted drugs can produce a positive reaction with the antibodies (cross-react), causing a false, positive result. To reduce this possibility, many tests favor a negative result, following the philosophy that it is more important to minimize false, positive results than to identify every drug user.

In general, the more sensitive the test, the more likely the chance for false, positive results. Conversely, the less sensitive the test, the less likely it is to detect the true presence of drugs.

Given the fact that drug-testing programs exist to identify drug users and reduce a company's liability, this may be somewhat disconcerting. Every positive result must be confirmed by a second, highly specific technology. Negative results are accepted by screening tests alone. Though little experimentation has been reported to document the percentage of false, negative samples, it is clear that reporting a negative, at least for the laboratory, is making the safer choice.

Double checking

By definition, drug test confirmation in workplace drug testing implies the use of a technology known as GC/MS (Gas Chromatography/mass Spectrometry). The GC/MS system looks at the most elemental parts of drug compounds. In the instrument, molecules of a drug compound are broken into smaller, electrically charged fragments called ions. The collection of ions from the fragmented molecules are recorded by the instrument in the form of a bar graph called a mass spectrum. A complete mass spectrum of a drug is as unique as a fingerprint.

However, techniques to perform GC/MS differ. A common technique known as selected ion monitoring (SIM) collects and examines three unique ions of a compound in order to identify a drug. Another technique, called full scan, examines all the ions present in a way comparable to examining a fingerprint. In human testing, no regulation exists as to what technique laboratories use. Surprisingly, in dog- and horse-race testing, full-scan GC/MS is mandated. Although both techniques are extremely reliable, the technology is not absolutely foolproof.

How false results occur

Far and away the primary cause of false results is human error. Samples that are handled carelessly, information entered incorrectly, or techniques not followed precisely can all contribute to error. These kinds of errors will most likely result in a sample being called negative, except in a case in which two samples are confused. In most labs, careful documentation and chain-of-custody procedures can virtually eliminate this possibility.

As noted earlier, many screening tests cross-react with compounds other than the drugs targeted in the test, producing a false, positive result. Again, without confirmation testing, the likelihood of a false, negative result is actually much more probable.

GC/MS is held as "the gold standard" in confirming positive drug-screenin tests, but is not (as laboratories may claim) 100 percent accurate. In a recent issue of Clinical Chemistry (Vol. 37, No. 7, 1991, p. 1305), the authors describe how the prescription drug Ritodrine interferes with one of the internal standard ions of a marijuana metabolite, causing a false, negative result under SIM. Because the technique looks at only three ions and determines the ratio of each to the others, another compound with the same ion can throw the ratio off. Ritodrine has exactly this effect. Because full-scan GC/MS looks at all the ions and does not depend on the ratio, the authors confirmed this assumption with the full-scan technique.

The inherent danger, though arguable, is that a legal drug or other compound exists with exactly the same three ions as the illegal drugs. This kind of compound could, in theory, produce a false positive result.

What's an HR manager to do?

If you choose a laboratory that's certified to test samples for the federal or state government or is certified by an institution such as the College of American Pathologists, it's likely that the results you receive will meet your needs for accuracy and safety. However, you can make some choices to affect the quality of your program.

Depending on where your employees are located, the instance of drug use in those areas, and the nature of the work they do, you may want to specify drugs other than the "NIDA-5" to target for your employees. You may also want to accept lower levels as positive results. You may also consider testing for truly unknown drugs (not targeted) by more sophisticated instruments.

If you perform only pre-employment screening and test a limited number of applicants each year, consider confirming all tests both positive and negative by GC/MS for absolute confidence. You'll probably find this alternative cost prohibitive if you hire many employees each year.

Accept only a positive result that is confirmed by a second, more definitive technique and ask how tests are confirmed. GC/MS confirmation is mandated by the federal guidelines and may soon be mandated for all drug-testing labs by law. Also, remember there are different kinds of GC/MS techniques.

The issue of false negatives and the absolute accuracy of drug testing will not be totally resolved until additional study is provided to address the unanswered questions. How many screened negatives actually contain drugs? What percentage of GC/MS confirmed positive results do not have the identified drug present? NIDA conducts proficiency testing, which could shed light on the false negative question, but they do not release results of the entire proficiency-testing program. As for false positives, no program is currently in place to retest SIM-confirmed results with more sophisticated methods.

Legislation has been proposed to include testing for additional drugs in federal programs and to regulate all labs more closely. Let your legislator know how you feel about the issues surrounding drug testing, and you can be part of making the workplace truly a drug-free environment.

They Test Horses, Don't They?

Not unlike testing in the workplace, drug testing at horse and dog racetracks throughout the country uses urine samples taken from racing animals to detect illegal drug administrations.

The objective of state racing commissions is to safeguard the racing industry from drug abuses that impact the fairness, safety and livelihood of racing. Administration of illegal drugs to racing animals was detected in the early 1900s and led to policies that control which drugs may be legally administered to racing animal prior to a racing event.

Ironically, animal testing mandates even higher-confidence analytical techniques that human testing in the workplace. That means the horse may be held to a higher standard than the jockey.

While chain of custody, sample screening and GC/MS confirmation are all a part of animal drug detection, how confirmation is performed differs. Unlike workplace testing, the laboratory process in animal testing requires the use of the full-scan technique of GC/MS drug confirmation. Why?

What's different is the challenge involved in detecting and identifying any of more than 200 drugs available for use by owners, trainers and track personnel. Often, drugs used in animals have never been "seen" by laboratories performing the drug tests. The task is enormous, yet it must be performed in very short time periods, typically within 24 hours. The full-scan precedent is also based on the desire to hold test results to the highest degree of confidence. This provides the laboratory with evidence to defend their results in racing commission hearings or court.

COPYRIGHT 1992 Society for Human Resource Management
COPYRIGHT 2004 Gale Group