Drug Testing| Frequently asked questions (FAQ)

When is Drug Testing required?
Understanding when to test is directly linked to which drug testing solution you or your organization should select.

  • Pre-employment testing helps employers proactively protect themselves from the negative impacts of hiring drug users.  
  • Random testing is conducted on an unannounced basis. By using a random selection process, all employees have an equal chance of being selected
  • Periodic testing is typically performed at consistent periods throughout the year. 
  • Post-accident testing is performed after an employee has been involved in a workplace accident. This should be performed as soon as possible.
  • Reasonable suspicion testing is performed when employers have evidence or reasonable cause to suspect an employee of drug use.

What does ng/mL refer to?
Nanograms per millilitre, abbreviated ng/mL, is the unit of measure most commonly used to express drug testing cut-off levels and quantitative test results in urine and oral fluid. A nanogram is 10-9 grams. 

What methodologies do we use to perform confirmatory testing?
Gas chromatography/mass spectrometry (GC/MS) is the method we use to confirm presumptive positive drug screens. These mass spectrometric methodologies provide identification of the molecule(s) based on characteristic fragmentation patterns at specific retention times.

What methodology do we use to perform initial drug screening?
We perform initial drug screening using immunoassay based drug test cups. An immunoassay is a test that uses antibodies to detect the presence of drugs and other substances in the urine. The initial screening process does not measure the specific amount of drug present in urine samples. It provides either a negative or a presumptive positive result, indicating the absence or possible presence of detectable drug relative to a ‘threshold’ or ‘cutoff’ concentration.

What are the different types of drug tests?
Urine is the most common specimen for drug screening. Urine drug testing detects recent drug use and is the only testing method approved for federally-mandated testing. Other specimens include Oral Fluid, Hair, Blood and Sweat.

What are the different methods of Drug Testing?
Urine:  Results of a urine test show the presence or absence of drug metabolites in a person’s urine.  Metabolites are drug residues that remain in the body for some time after the effects of a drug have worn off.  It is important to note that a positive urine test does not necessarily mean a person was under the influence of drugs at the time of the test.  Rather, it detects and measures use of a particular drug within the previous few days and has become the defacto evidence of current use.  Because alcohol passes rapidly through the system, urine tests must be conducted very quickly after alcohol consumption in order to ensure any degree of accuracy.  For this reason, urine tests are generally not helpful in detecting alcohol use as opposed to illicit and prescription drug use, which is more easily traced in urine.    

Breath:  A breath-alcohol test is the most common test for finding out how much alcohol is currently in the blood.  The person being tested blows into a breath-alcohol device, and the results are given as a number, known as the Blood Alcohol Concentration (BAC), which shows the level of alcohol in the blood at the time the test was taken.  BAC levels have been correlated with impairment, and the legal limit of 0.08 for driving has been set in all states.  Under DOT regulations, a BAC of 0.02 is high enough to stop someone from performing a safety-sensitive task for a specific amount of time (usually between 8 and 24 hours) and a BAC reading of 0.04 or higher is considered to be a positive drug test and requires immediate removal from safety-sensitive functions.  Under DOT regulations, a person who tests at the 0.04 BAC level may not resume job duties until a specific return-to-duty process has been successfully completed.

Blood:  A blood test measures the actual amount of alcohol or other drugs in the blood at the time of the test.  Blood samples provide an accurate measure of the physiologically active drug present in a person at the time the sample is drawn.  Although blood samples are a better indicator of recent consumption than urine samples, there is a lack of published data correlating blood levels for drugs and impairment with the same degree of certainty that has been established for alcohol.  In cases of serious injury or death as the result of an accident, the only way to determine legal intoxication is through a blood specimen.  There is also a very short detection period, as most drugs are quickly cleared from the blood and deposited into the urine.

Hair:  Analysis of hair provides a much longer “testing window,” giving a more complete drug-use history going back as far as 90 days.  Like urine testing, hair testing does not provide evidence of current impairment, but rather only past use of a specific drug.  Hair testing cannot be used to detect for alcohol use.  Hair testing is the least invasive form of drug testing, therefore privacy issues are decreased.

Oral Fluids:  Saliva, or oral fluids, collected from the mouth also can be used to detect traces of drugs and alcohol.  Oral fluids are easy to collect (a swab of the inner cheek is the most common collection method), harder to adulterate or substitute, and may be better at detecting specific substances, including marijuana, cocaine and amphetamines/methamphetamines.  Because drugs do not remain in oral fluids as long as they do in urine, this method shows promise in determining current use and impairment. 

Sweat:  Another type of drug test consists of a skin patch that measures drugs in sweat.  The patch, which looks like a large adhesive bandage, is applied to the skin and worn for some length of time.  A gas-permeable membrane on the patch protects the tested area from dirt and other contaminants.  Although relatively easy to administer, this method has not been widely used in workplaces and is more often used to maintain compliance with probation and parole.

What is the detection window?
The amount of time after ingestion during which evidence of drug use can be detected by a drug test is call the Detection Window. Alcohol is absorbed and eliminated more quickly than other drugs. This is why post-accident testing procedures often require testing for alcohol to occur within two hours. Other drugs are eliminated from the system at different rates and thus detectable for different periods of time, often long after the drug;s effect has worn off. The following are estimates of the length of time that certain drugs are detectable:

  • Alcohol – 1 oz. for 1.5 hours 
  • Amphetamines – 48 hours 
  • Barbiturates – 2-10 days 
  • Benzodiazepines – 2-3 weeks 
  • Cocaine – 2-10 days 
  • Heroin Metabolite – less than 1 day 
  • Morphine – 2-3 days 
  • LSD – 8 hours 
  • Marijuana – casual use, 3-4 days; chronic use, several weeks
  • Methamphetamine – 2-3 days 
  • Methadone – 2-3 days 
  • Phencyclidine (PCP) – 1 week 

What drugs to test detect?
Testing conducted according to SAMHSA’s guidelines checks for five illicit drugs plus, in some cases, alcohol (ethanol, ethyl alcohol, booze).  These five illicit drugs are: 

  • Amphetamines (meth, speed, crank, ecstasy)
  • THC (cannabinoids, marijuana, hash)
  • Cocaine (coke, crack)
  • Opiates (heroin, opium, codeine, morphine)
  • Phencyclidine (PCP, angel dust)  

However, most private employers are not limited in the number of substances they can test for and may include drugs that individuals legitimately and/or therapeutically take based on a physician’s prescription.  Although most private employers can test for any combination of drugs, there are commonly selected “panels.” 

However, most employers can test for any combination of drugs base on their requirements.

How does a drug test determine if a person has been using substances?  What are cut-off levels and what do they determine?
Aside from a breath alcohol test, drug testing does not determine impairment or current drug use.  Rather, drug testing determines a specified amount or presence of a drug or its metabolite in urine, blood or an alternative specimen.  There is a minimum measurement applied to drug testing so that only traces of a drug or its metabolite above a specified level is reported as positive.  This measure is known as a “cut-off level,” and it varies for each drug.  Setting cut-off levels involves understanding the expected results of testing and determining the needs of the employer’s drug-free workplace program.  For instance, if a cut-off level is set low, test results will come back with more “false positives” as some “passive” users could test positive.  (For example, a low cut-off level could cause a positive result from consuming poppy seeds.)  Conversely, a high cut-off level will result in more “false negatives,” and thus some users may go undetected.  However, a high cut-off level lessens the likelihood of taking action against someone based on “passive” exposure, and for this reason SAMHSA’s guidelines set cut-off levels on the high side. 

Source: https://www.datia.org/datia-resources/27-credentialing/cpc-and-cpct/931-workplace-drug-testing.html

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