A Study On Drug Testing Biology Essay

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To screen for drug use, to monitor someone with a substance abuse problem, or to detect and evaluate a drug overdose

When to Get Tested?

Prior to the start of a new job or insurance policy, at random for workplace drug testing and athletic drug testing programs, as mandated when court ordered, as indicated when ordered by a doctor to monitor a known or suspected substance abuse patient, or whenever a person has symptoms that suggest a drug overdose

Sample Required?

A random urine sample; sometimes a blood sample drawn from a vein in your arm; rarely hair, saliva, or sweat

Test Preparation Needed?

Drugs of abuse testing is the detection of one or more illegal and/or legal substances in the urine or, more rarely, in the blood, saliva, hair, or sweat. It usually involves an initial screening test followed by a second test that identifies and/or confirms the presence of a drug or drugs. Most laboratories use commercially available tests that have been developed and optimized to screen urine for the "major drugs of abuse."

For most drugs of abuse testing, results of initial screening testing are compared with a predetermined cut-off. Anything below that cut-off is considered negative; anything above is considered a positive screening result.

Within each class of drug that is tested, there may be a variety of chemically similar drugs. Legal substances that are chemically similar to illegal ones can produce a positive screening result. Therefore, screening tests that are positive for one or more classes of drugs are frequently confirmed with a secondary test that identifies the exact substance present using a very sensitive and specific method, such as gas chromatography/mass spectrometry (GC/MS).

Some of the most commonly screened drug classes are listed in the table below.

Drug class screened

Examples of specific drugs identified during confirmation


Methamphetamine, amphetamine


Phenobarbital, secobarbital, pentobarbital


Diazepam, lorazepam




Cocaine and/or its metabolite (benzoylecognine)


Codeine, morphine, metabolite of heroin

Phencyclidine (PCP)


(See a more comprehensive list of drug classes and drugs of abuse.)

Substances that are not similar to the defined classes can produce false negative results. Some drugs may be difficult to detect with the standardized assays, either because the test is not set up to detect the drug, such as methylenedioxy-methamphetamine (MDMA, Ecstasy), oxycodone (Oxycontin), or buprenorphine, or because the drug does not remain in the body long enough to be detected, such as gamma-hydroxybutyrate (GHB).

For sports testing of hormones and steroids, each test performed is usually specific for a single substance and may bequantitative. Athletes, especially those at the national and international level, are tested for illegal drugs and are additionally governed by a long list of prohibited substances called performance enhancers.

Groups of drug tests are typically ordered for medical or legal reasons, as part of a "drug-free workplace" or as part of a sports testing program. People who use these substances ingest, inhale, smoke, or inject them into their bodies. The amounts that are absorbed and the effects that they have depend on the which drugs are taken, how they interact, their purity and strength, the quantity, timing, method of intake, and the individual person's ability to metabolize and excrete them. Some drugs can interfere with the action or metabolism of other medications, have additive effects such as taking two drugs that both depress the central nervous system (CNS), or have competing effects such as taking one drug that depresses the CNS and another that stimulates it. The drugs tested for are not normally found in the body, with the exception of some hormones and steroids measured as part of sports testing.

How is the sample collected for testing?

Urine is the most frequently tested sample, but other body samples such as hair, saliva, sweat, and blood also may be used for drug abuse screening but not interchangeably with urine.

Urine and saliva are collected in clean containers. A blood sample is obtained by inserting a needle into a vein in the arm. Hair is cut close to the scalp to collect a sample. A sweat sample is typically collected by applying a patch to the skin for a specified period of time.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

How is it used?

Drug of abuse testing may be used in one of several different ways:

Medical screening

Legal or Forensic testing

Employment Drug testing

Sports/Athletic testing

Medical Screening 

Medical screening for drugs of abuse is primarily focused on determining what drugs or combinations of drugs a person may have taken so that he can receive the proper treatment. The overall effect on a particular person depends on the response of his body to the drugs, on the quantity and combination he has taken, and when each was taken. For instance, MDMA is initially a stimulant with associated psychedelic effects, but it also causes central nervous system (CNS)depression as it is metabolized and cleared from the body. In many cases, drugs have been combined and/or taken with ethanol (alcohol). If someone drinks ethanol during this time period, they will have two CNS depressants in their system, a potentially dangerous combination.

Those who may be tested for drugs for medical reasons include:

Someone in the emergency room who is having acute health problems that the doctor thinks may be drug-related: unconsciousness, nausea, delirium, panic, paranoia, increased temperature, chest pain, respiratory failure, seizures, and/or headaches.

Someone in the emergency room who has been in an accident, when the doctor suspects that drugs and/or alcohol may have been involved.

A youth or adult who the doctor suspects may be using drugs.

Those who are being monitored for known drug use. This may include both legal and illegal drug use. It may be general testing or specific for the substance that has been abused.

Pregnant women thought to be at risk for drug abuse or neonates exhibiting certain characteristic behaviors.

Legal or Forensic Testing  

Drug testing for legal purposes is primarily concerned with the detection of illegal or banned drug use in a variety of situations. Sample collection procedures for this type of testing are strictly controlled and documented to maintain a legal "chain-of-custody." The donor provides a sample that is sealed and secured with a tamperproof seal in his or her presence. Specific chain-of-custody paperwork then accompanies the sample throughout the testing process; each person who handles and/or tests the sample provides their signature and the reason for the sample transfer. This creates a permanent record of each step of the process. Examples of legal drug abuse screening include:

Court-mandated drug testing usually involves the random monitoring of someone who has been convicted of illegal drug use. Testing may also be ordered in custody cases to rule out drug use by one or both parents.

Government child protective services may sometimes require extended monitoring of a parent with a known drug problem to ensure that they have not returned to drug use.

Law enforcement drug testing may be done when someone has an accident that is suspected to be alcohol- or drug-related.

Forensic testing utilizes a variety of body fluids and tissues that may be tested for numerous drugs during a crime investigation. The goal may be to determine whether drugs were a contributing factor to an accident or crime, such as a DUI or rape. Testing may also be done to determine whether someone died of a drug overdose or drug-related condition.

Insurance companies may perform drug screening on their applicants. This may include a test for cocaine and a test for nicotine, even though tobacco is a legal substance.

Schools may have programs that incorporate random drug testing. This may include illegal drugs of abuse and, with competitive sports, may include testing for performance-enhancing substances.

Employment Drug Testing 

Employment drug testing may be done prior to employment, on a random basis, following an accident, or if the employer has a reasonable suspicion that their employee is using illegal drugs. The major drugs of abuse are tested, and any positives are confirmed by another method. Employment drug testing is commonplace. It is required in some industries, such as those that involve the U.S. Department of Transportation or federal employees, and accepted practice in many other industries.

As with legal or forensic drug testing, the sample collection and testing procedures for employment drug testing are often strictly controlled and documented to maintain a legal "chain-of-custody." A sample is obtained (usually a urine sample) from the employee in a container that is secured with a tamperproof seal in his or her presence. Specific chain-of-custody paperwork then accompanies the sample throughout the testing process and documents each person who handles and/or tests the sample. This creates a permanent record of each step of the process.

Sports/Athletic Screening 

While conventional drug testing is performed on competitive athletes, the primary focus is on doping - drugs and/or supplements that are taken to promote muscle growth and/or to improve strength and endurance. On a local level, sports testing may be limited, but on a national and international level, it has become highly organized.

The World Anti-Doping Agency (WADA), U.S. Anti-Doping Agency (USADA), and the International Association of Athletics Federations (IAAF) work together to monitor athlete drug use on a national, international, and Olympic level. WADA has a written code, which establishes uniform drug testing rules and sanctions for all sports and countries, and a substantial list of prohibited substances. Athletes are responsible for any banned substances that are found in their body during testing. Most of the compounds tested are considered positive if they are detected in any quantity while others, such as caffeine, are only prohibited when they are present in large amounts. Some of the substances, such as anabolic steroids (testosterone) and peptide hormones such as erythropoietin, growth hormone, and Insulin-like Growth Factor-1 are banned but are difficult to measure as they are produced by the body. Testing methods must be able to distinguish between endogenous (that produced by the athlete's body) and supplemented compounds.

Screening programs randomly perform out-of-competition drug tests on athletes during the training season to look for anabolic steroids, such as testosterone, that promote increased muscle growth. During competitions, testing is frequently done both randomly and on all winners and includes categories such as: stimulants, narcotics, anabolic agents, and peptide hormones. Sports such as archery, gymnastics, and shooting add additional testing for substances like beta blockers, which are prohibited in these sports because they decrease blood pressure and heart rate.

While professional sports organizations, such as the NFL (National Football League), NHL (National Hockey League), and NBA (National Basketball Association), are not covered by the WADA code, they have programs in place to test their athletes for panels of drugs that combine aspects of sports and employment testing. Those professional athletes who also take part in the Olympics, however, are subject to the same out-of-competition (pre-game) and in-competition testing as other competing athletes.

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When is it ordered?

Drug testing is performed whenever a doctor, employer, legal entity, or athletic organization needs to determine whether a person has illegal or banned substances in his body. It may be ordered prior to the start of some new jobs and insurance policies, at random to satisfy workplace and athletic drug testing programs, as mandated when court ordered, as indicated when ordered by a doctor to monitor a known or suspected substance abuse patient, and whenever a person has symptoms that suggest drug use.

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What does the test result mean?

If a result is positive during initial drug screening, then it means that the person has a substance in his body that falls into one of the drug classes and is above the established cutoff level. If the sample is confirmed as positive after secondary testing, such as positive for marijuana, then the person has taken this drug. In some cases, this result can be tied to a window of time that the person took the substance and roughly to the quantity but, in most circumstances, that information is not necessary. Interpretation of when and how much drug was consumed can be challenging because the concentration of many drugs varies, as does their rate of metabolism from person to person.

If the drug or drugs is not present or is below the established cutoff, then the result is usually reported as "not detected" or "none detected." A negative result does not necessarily mean that the person did not take a drug at some point. The drug may be present below the established cutoff, the drug may have been already metabolized and eliminated from the body, or the test method does not detect the particular drug present in the sample.

Urine testing shows drug use over the last 2 or 3 days for amphetamines, cocaine, and opiates. Marijuana and itsmetabolites, cannabinoids, may be detectable for several weeks. Hair samples, which test the root end of the hair, reflect drug use within the last 2 to 3 months but not the most recent 2-3 weeks - the amount of time it takes for the hair to grow. Saliva detects which drugs have been used in the last 24 hours. Samples of sweat may be collected on an absorbent patch worn for several days to weeks and therefore can indicate drug use at any point during that extended period of time. These other types of samples are often used for specific purposes. For instance, hair samples may be used as an alternative to urine testing for employment or accident drug testing. Sweat testing may be used as a court-ordered monitoring tool in those who have been convicted of drug use, while saliva is often used by the insurance industry to test insurance applicants for drug use. Blood is most frequently used for alcohol testing.

Interpretation of sports testing results for hormones and steroids should be done by someone who is familiar with the test methods. A negative result indicates that there is a "normal" amount of the substance present in the body. Positive results reflect the presence of the substance above and beyond what is normally produced by the athlete's body. This can be complicated by the fact that each person will have their own normal baseline concentration and will produce varying amounts of hormones and steroids, depending upon the circumstances.

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Is there anything else I should know?

Symptoms associated with drug abuse and drug overdose will vary from person to person, from time to time, and do not necessarily reflect drug concentrations in the body.

Ethanol may be measured in both the blood and the breath. This is the basis for the breathalyzer test used by law enforcement.

For some types of testing, such as workplace testing of federal employees, there are many regulations that cover the test from collection through interpretation and reporting of results. It is important for the ordering physician, law enforcement representative, forensic professional, government entity, insurance agent, employer, and sports organization as well as for the person being tested to understand what exactly is included in the testing, how it is done, and how the results may or may not be interpreted. This process is not nearly as simple or straightforward as collecting a sample and requesting "drug testing."

Certain prescription and over-the-counter drugs may give a positive screening result. You should declare any medications that you have taken and/or for which you have prescriptions when you have a drug test so that your results can be interpreted correctly. Also, poppy seeds that have not been washed can cause a positive opiate screening result if eaten, for example, with a bagel or muffin. You may want to avoid these foods if you have drug testing done.