Pre-employment drug testing

This is by far the most common type of drug test used by businesses, however, it is also the least effective. It is considered to be an “intelligence test” by drug testing professionals. It has the advantage of being inexpensive, since only one test per employee needs to be paid for by the company. However, since most pre-employment drug testing is urine-based and subject to sample adulteration or substitution, the effectiveness of this approach has been questioned by federal legislators. Some organizations have a witness in the room at the time of the testing, but the privacy implications of this, as well as the potential for shy bladder syndrome has limited the use of witnesses outside jails and drug treatment programs. Companies and testing centers that do not use witnesses normally disconnect sources of water from the testing room to discourage dilution, and if there is water in the toilet, it is dyed blue. Other countermeasures, such as making the donor change into a gown, may also be used.

Random drug testing

Random drug testing is the most effective format. In the USA, random drug testing is used by a growing number of corporations, drug rehab centers, prisons, the military, police and fire departments, government agencies, and more recently, schools. It may also be used on teens by their parents, or mandated to be performed at school. The objective of a random drug test is deterrence, as the threat of detection is much higher versus other testing methods. Various random selection methods are used, ranging from drawing names out of a hat to using random number generators.

Critics of random testing claim that random drug testing introduces a presumption of guilt, and is a violation of privacy if the drug user is not actually intoxicated during working hours. In addition, urine-based random testing is more likely to catch cannabis users, since THC metabolites are fat soluble and have a longer duration in the body than those of many other drugs.

Post-incident drug testing

Post-incident drug testing is not a very commonly administered test compared to the other two, but the financial ramifications of not testing employees after an accident (or other incident) on the job makes this test worthwhile for most businesses. The point of this test is not necessarily to cause the employee to lose his or her job, but rather to protect the company from liability in the event that the individual is under the influence at the time of the accident. If drugs or alcohol are detected in any significant quantity, the argument can be made in court that the individual was intoxicated on the job, and for that reason, the company should not be held liable for injuries sustained by the employee. This argument, however, can only reasonably be made if blood or oral fluid / saliva testing is used. Urine, hair, or sweat based testing can only detect past drug use. Depending upon the facts of each case, this may help a company avoid litigation completely or may do nothing to help their case. DUI testing would also fall into this category. Another time this type of test may be used is if an employee shows up for work intoxicated, has alcohol on his or her breath, or appears to be impaired in some other way.

The sample should follow chain of custody requirements and should always be sent to a lab after collection. Positive on-site tests that may affect an employee’s position or situation should always be followed up with a laboratory test before any action is taken against the employee.

Diagnostic screening

In the case of life-threatening symptoms, unconsciousness, or bizarre behavior in an emergency situation, screening for common drugs and toxins may help find the cause, called a toxicology test or tox screen to denote the broader area of possible substances than self-administered drugs. The test is usually done within 96 hours (4 days) after the estimated time of intoxication. Both a urine sample and a blood sample may be tested.[18]

Similar screenings may be used in to evaluate the possible use of date rape drugs. This is usually done on a urine sample