Understanding The Facts About Drug Testing

Many companies in the United States these days require drug testing as a condition of employment for new hires. Statistics provided by the US Surgeon General's office indicate that abusers of drugs and alcohol are responsible for removing more than $700 billion from the nation's economy on an annual basis. Those losses are related to health care, crime and loss of work productivity. Employers, of course, are most concerned about the loss of productivity, but they also need to worry about workplace safety. 


Some companies will only require job applicants to undergo drug testing before they can be hired. There are some instances where current employees may be asked to take a drug test. This happens in some cases after an on-the-job accident that was caused by human error and led to property damage or injury. Certain jobs that involve a high degree of safety may require employees to subject to random drug testing. This means that the employee can be tested at any time, even without any cause for suspicion. 


Companies that want to implement a drug screening program must contract with a certified and reputable laboratory that uses approved methods for testing. The best labs will use a two-step process to confirm a positive result. This ensures that there is very little opportunity for inaccurate results. The most common method used involves an initial immunoassay test followed by a gas chromatography-mass spectrometry or GC-MS test. Among the most popular national drug testing labs are Lenexa, National Toxicology Labs, Inc., and Quest Diagnostics, Inc.


The lab will perform the immunoassay first. If the lab receives a negative result on this portion of the test, the screening result is noted as negative and no further testing is necessary. If the biological sample tests positive in the immunoassay test, a separate portion of the same sample is tested with GC-MS. This test is sensitive enough to identify the drugs present in the sample as well as any drug metabolites. This test can also quantify the amount of drug in the sample. 


Labs can use a variety of different biological samples to test for the drugs most commonly abused. The options include testing blood, hair, saliva, or urine. There are also different panels that test for different types of drugs. Some employers opt to use a five-panel test of the most common street drugs. Those drugs are amphetamines, opiates, PCP, cocaine, and marijuana. Some companies will request a nine-panel test that also detects MDMA, barbiturates, benzodiazepines and prescription narcotics. 


Blood testing is the most invasive way to test for drug use. The one advantage of a blood test is it determines how much of a drug is in the bloodstream at a specific point in time. This will tell for sure if someone has drugs in their system at the time of the test. Although blood tests are invasive and require a clinical environment for taking the sample, they are extremely reliable and almost impossible to corrupt. 


Hair is the preferred biological sample when the employer is interested in determining if someone has been abusing drugs over a longer term. This type of test can usually identify drug use over a period of 90 days. 


A saliva test is usually ordered if the employer is interested in finding out about recent drug use but is not really interested in a person's history of past drug use. Saliva samples are the easiest to collect because all they require are a simple swab of the inside of the cheek. Saliva tests are usually good for detecting usage from within a few hours to up to as long as three days. 


Urine tests are by far the most common tests ordered by employers. A urine sample will show the presence of most drugs even after the physical effects have worn off. The length of time a drug will show up in a urinalysis varies depending on the drug used.  


The length of time a drug is detectable in urine, blood, hair or saliva depends on a variety of factors. Those factors include route of delivery, the frequency of use, the testing lab's chosen cut-off concentration, the drug's half-life and the test subject's state of fluid balance and hydration.