Medical science and forensic science has been growing at a rapid pace. Just a few years ago DNA testing was in it’s infancy and the science of drug testing was also crude. There are now more methods of drug testing that have increased accuracy and the window of detection.

At the present time the four most common methods of drug testing are taking samples of urine, hair, oral fluids (saliva), and sweat (perspiration). Each method has it’s advantages and disadvantages.

Urine Samples

Urine samples remain among the most common type of drug testing primarily because of the low cost and accuracy of results. Urine testing has been around for awhile and the accuracy of urine test results is widely accepted in the legal and medical communities.

Urine testing can also detect a wide range of narcotics including the presence of alcohol and nicotine. The window of detection is typically one to five days which makes urine testing ideal for “spot” checks. (Abadinsky, 2004)

Since urine testing is so inexpensive, urine testing kits are now available in local pharmacies for home use. Home testing is becoming popular with parents who are suspect their children have been using drugs.

Urine testing is not without it’s challenges. Since urine testing has been around for a long time, drug addicts have learned how to get around the system. A common method to distort the test results include diluting the sample with water or drinking a large amount of water prior to the test. Another method includes substituting the sample by carrying in another person’s urine.

Obtaining a urine sample is also considered embarrassing. Test subjects are usually allowed to urinate into a sample container in privacy. This creates an environment where the test subject can dilute the results or switch samples without being noticed.

Urine is also considered a biological hazard. Medical technicians and test subjects may be uncomfortable with handling a sample.

To combat the alteration of test results using water or a substitute sample, urine tests are now typically conducted in a room that does not have running water (such as a bathroom). Test containers also contain strip thermometers to ensure that the sample is warm. If the sample is cold it is likely a diluted sample or a substitute sample that was smuggled in.

There are also verified cases of false positives. For example if a person consumes a large amount of poppy seeds prior to the test, a false positive for opiates may occur. Also certain prescription medications can cause a false positive. So, it is important to ask the test subject what medications they are taking prior to the test.

Hair Samples

Obtaining results using hair samples is a relatively new method of drug testing. This method can determine if the test subject has used drugs for a longer period than the other methods depending on how long the hair sample is. This makes hair samples a good way to detect chronic drug use. (Abadinsky, 2004)

Drug testing using hair samples is the most expensive method of drug testing. This type of test is usually only performed when absolutely necessary and is typically not used for random drug testing. (Abadinsky, 2004)

Hair samples are also easy to obtain, easy to transfer, and easy to store in comparison to taking biological fluids. Since the removal of a hair isn’t considered embarrassing the sample may be obtained in open view which guarantees the sample came from the person it is suppose have come from.

Hair samples are also much harder to distort than other samples. It would be almost impossible to dilute the sample. Hair also does not require refrigeration or special handling procedures like biological fluids require.

The most obvious disadvantage to a hair sample is that hair can be cut and discarded to prevent a quality sample. This gives an advantage to men who can simply shave their heads without enduring much social stigma. However women can also cut their hair and replace it with a wig.

Hair samples also cannot detect recent drug use within the period of one week. Tests are also limited to a 5-drug panel. Only certain drugs are detectable in hair follicles. Alcohol is not detectable.

Oral Samples

An oral sample or saliva collection is an alternative method to urine tests. Obtaining saliva is considered less embarrassing and less invasive then urine samples. The advantage would be that the sample is not obtained in private and therefore you can guarantee that a substitute or diluted sample is being obtained.

Oral drug testing is becoming more popular for “spot” testing and random drug testing. Oral testing can reveal recent drug use typically within the past 24 hours. Since it reveals recent drug use its a good test for ensuring the persons who operate machinery, or drive vehicles are not under the influence of narcotics.

The disadvantages of oral drug testing are that the test can only detect recent drug use. Evidence of drug use doesn’t not remain in saliva as long as it does in urine. Some drugs like marijuana are not detected well using oral drug testing. (Abadinsky, 2004)

Sweat Patch

Another relatively new method of drug testing is the sweat patch. This is a patch typically remains on the person for a few days to ensure the person does not take illegal narcotics during that period. The patch can also be applied and removed quickly for “spot” testing or random drug tests. (Hawkins, 2002)

The patch is also considered relatively non-invasive and doesn’t require privacy to apply or remove. Since the patch can remain on the skin for a few days it has a greater window of detection than a typical urine test.

Although, it’s considered less invasive than a urine test some people will not be able to tolerate the patch. People with sensitive skin or excessive hair might be bothered by the use of the patch and may experience pain upon the removal of the patch or the development of a skin rash.

The patch is also considered very susceptible to false positive results. Passive exposure to drugs may contaminate the patch. For example, being in the same room or vehicle when someone is smoking marijuana or handling illegal substances.

Since this is relatively new type of drug test, there are still few labs than can process the test results. Therefore the use of the patch drug test is limited at this time.

With any new type of drug test, there are also new legal challenges. This is true for the skin patch and limited it’s use. Agencies conducting drug tests will favor tried and true methods like urine testing, instead.

Conclusion

The driving force behind drug testing will continue to be cost. Cheaper drug tests like urine testing will be favored for this reason. This is especially true for common “spot” tests and random drug testing. Employers and government agencies are concerned more with the bottom line then the accuracy and invasiveness of drug tests.

As discussed, different drug tests are suitable to different situations. For example, a convicted drug offender on probation might have several random tests using a urine sample, and once every six months have a hair sample taken.

False positive and negative results will also continue to be a major issue and legal challenge to drug tests. A false positive result could result in severe ethical and legal implications including the loss of a job or career. Meritorious lawsuits proving a false positive could result in settlements and judgments for large amounts of money as a result of the loss of financial livelihood. On the other hand, false negatives and tampering could result in the continued drug use of persons who are responsible for the safety of the public including airplane pilots, truck drivers, machine operators, and public safety officials. A drug addicted person could potentially cause harm to themselves or the general public. Deaths and injuries could result. (Hawkins, 2002)

The development of less expensive, and more accurate drug testing methods is a crucial need. Employers and government agencies responsible for ensuring the public safety need accurate results at a minimal financial cost.

The ethics of drug testing and privacy will also continue to be an issue. Who should get drug tests and who shouldn’t? Where do we draw the line? There is also a bias towards the blue collar workforce who is subjected to drug tests more than while collar professionals. Civil rights issues linger, do we have a right to privacy when it comes to what we put in our bodies?

References

Abadinsky, Howard. (2004). Drugs: An Introduction. Belmont, CA.: Thomson Wadsworth.
Hawkins, Dana. (August 12, 2002). Tests on Trial: Jobs and Reputations Ride on Unproven Drug Screens. U.S. News and World Report.
Office of National Drug Control Policy (2002). What You Need to Know About Drug Testing in Schools. Washington DC: U.S. Government Printing Office

APA Citation:
Smith, Nathan. M. (2007). Drug Testing Methods.
Retrieved September 8, 2008, from http://www.computer-forensic-technician.com/wordpress/drug-testing-methods/.