It is important to be sure that the drug testing occurs at a reputable and certified laboratory. Any credible drug screening program will involve a two-step process.

• Initial (immunoassay) and confirmatory (gas chromatography-mass spectrometry [GC-MS]  or liquid-mass spectrometry [LC/MS) test) are the methods most commonly utilized to test for drugs.
• Using a combination of both tests allows a high level of sensitivity and specificity, meaning there is an extremely low chance for false positives or false negatives.

The immunoassay is performed first and is often used as a screening method. If the immunoassay is negative, no further action is typically required, and the results are reported as negative.

If the sample is positive, an additional confirmatory GC/MS analysis is performed on a separate portion of the biological sample. The more specific GC/MS or LC/MS is used as a confirmatory test to identify individual drug substances or metabolites and quantify the amount of the substance.

Confirmatory tests, such as GC-MS or LC-MS should be utilized prior to reporting positive drug test results to employers.

Urine and oral fluid specimens are the only sample type approved for testing of the federally mandated, safety-sensitive workforce.

Urine drug testing

Urine is the most common sample type used for drug testing by employers. A urinalysis will show the presence of a drug in the system after the drug effects have worn off, but the length of time varies by drug. 

Typical urine drug tests for employment purposes usually screen for 5 to 10 drugs. Urine screening may detect amphetamines or methamphetamines, barbiturates, benzodiazepines, cocaine, marijuana, MDA-analogues (MDA or MDMA known as Ecstasy), opiates (codeine, morphine, 6-acetylmorphine [indicative of heroin use], hydromorphone, hydrocodone, oxymorphone, oxycodone), nicotine, or alcohol.

Employers may request additional drugs to be screened.

Saliva drug testing

After urine drug screening, oral fluid (saliva) testing is the most common method to test for drug use. It may be referred to as a mouth swab test, and used if an employer or other tester is interested in knowing about recent drug use. It is not ideal to survey long-term use of drugs. Most saliva drug tests can detect usage within a few hours up to 2 days. The donor should avoid any food or beverages for at least 10 minutes prior to the sample being collected.

Saliva is an easy lab test to gather samples, is less susceptible to adulteration or substitution, and can be tested for alcohol, barbiturates, benzodiazepines, cocaine, ecstasy, marijuana (THC), opiates, amphetamines, phencyclidine (PCP), and methamphetamines. It is suitable for all testing reasons, including pre-employment testing, random and post-accident testing.

Blood drug testing

A blood drug test may be used to determine amounts of drug in an employee’s system at that very moment, usually from minutes to hours. It allows an employer or law enforcement official to determine if a person is actively under the influence of drugs or alcohol. Blood testing may also be performed in the emergency room for toxicology testing, as well.

A variety of drugs can be tested for in blood, examples include alcohol, amphetamines, cocaine, fentanyl, marijuana, methamphetamines, opiates, phencyclidine, nicotine, and tramadol.

Blood testing is invasive, requiring a needle stick into a vein, but there is little chance for adulteration. However, blood analysis often has a short period of detection, as many illicit drugs are metabolized quickly and eliminated from the body. Drugs in urine can usually be detected in a 1 to 3 day time period.

Hair drug testing

Hair testing may be used to determine drug use over the longer term, usually over a 90-day period of time. Hair can be tested for cocaine, marijuana and THC, cocaine, opiates, amphetamine and methamphetamine, ecstasy, phencyclidine, and alcohol. In general, hair testing allows the longest time frame to detect drugs of abuse.

The collector usually takes a 100 gram sample of hair (100 to 120 strands) cut close to the scalp. This method lessens the risk for hair adulteration or substitution, as the sample is collected in full view of the lab personnel.

Rapid tests

Rapid screening can allow detection of drugs that might metabolize quickly and not be detectable at a later screening. Screening for most drugs of abuse and alcohol can be performed. Rapid tests can be performed at an employer’s workplace or at a local, specified laboratory clinic. 

Rapid tests often utilize urine or saliva for testing. One advantage to rapid tests is that they provide a screening result within 4 hours on average. Any specimens that screen positive would still require a confirmatory test. Confirmatory test results are typically available in 2 to 3 days.