How Does Employment Drug & Alcohol Testing Work?

How Does Employment Drug and Alcohol Testing Work?

Drug testing in the workplace is a standard practice that virtually all applicants expect to find in the hiring process of any company. The reasons for employers to screen for drug use among their candidates and existing personnel may seem obvious, but it’s important to have a clear understanding of each of the most common reasons in order to create company drug and alcohol test policies that are comprehensive and effective as well as compliant with Federal and state laws and regulations.
So why do employers choose to perform drug and alcohol tests on prospective and current employees? The most common reasons for workplace drug testing are:
  1. To foster a safe and healthy work environment for employees and customers.
  2. To help the company benefit from Workers’ Compensation Premium Discount programs.
  3. To identify and disqualify candidates who use illegal drugs.
  4. To deter drug and/or alcohol abuse among the company’s current employees.
  5. To identify and appropriately refer current employees who have problems with drug and/or alcohol abuse.
  6. To comply with state and Federal laws and regulations (i.e. the U.S. Department of Transportation’s rules for drug testing employees who fill certain safety-sensitive positions.)
  7. To promote employee and customer confidence in the company’s commitment to quality and safety.

When are Drug Tests Conducted?

Of all the circumstances in which an organization may require a drug test, pre-employment testing is the most common. But there are many more occasions that could be written into an organization’s policies. These include:

Pre-Employment Testing

Following a conditional offer of employment, the applicant agrees to be tested, understanding that the offer will be withdrawn if the test proves positive. Because applicants can prepare for pre-employment testing by abstaining from drug use for several days beforehand, some employers choose to perform additional unannounced tests on probationary employees, but some states restrict this practice.
Employers across the board, however, are prohibited from performing pre-employment testing for alcohol use, per the Americans with Disabilities Act (ADA). Furthermore, with pre-employment testing, it’s all or none, meaning that employers cannot be selective about the applicants they choose to test at this stage.

Testing Based on Reasonable Suspicion

Also referred to as “probable-cause” or “for-cause” testing, reasonable suspicion testing is performed when a supervisor has observed and documented the signs and symptoms of drug use in an employee. Unlike pre-employment testing, this type of testing is discretionary and as such it’s crucial that the organization’s supervisor training program includes clear and consistent definitions of the “signs and symptoms of drug use” to look out for, and that their suspicions be corroborated by someone else in management. Another best practice is to prohibit the employee suspected of drug use or a drug-free workplace policy violation from returning to work until the results of the test are returned.

Post-Accident Testing

Objective criteria that is often used to trigger a post-accident test on an employee include an incident that results in:
  • fatalities,
  • injuries requiring off-site medical care,
  • property damage exceeding a specified dollar amount,
  • and police citations.
However, some employers choose to label this type of testing as “post-incident” to cover any event in which accident or injury could have occurred, but was fortunately averted, in order to rule out the presence of drugs and/or alcohol as a factor in the incident. Again, best practice dictates that the employee not return to work until the results of the test are returned, and that testing be conducted within 12 hours of the incident.


This type of testing has no advanced notice and, being unpredictable, is used as a deterrent for drug use. Subjects are drawn at random from an employee pool on a scientifically arbitrary basis to assure an equal chance for selection among all employees. Usually the selection is computer generated to guarantee its randomness, though this doesn’t eliminate the chance that an employee could be drawn two or more times in a row.


These tests occur uniformly across the employee base, usually on an annual basis and especially for positions that require regular physicals. Scheduled in advance, periodic tests can be planned for, unlike random testing policies, by abstaining from drug use for several days before the scheduled testing.


A one-time, announced test, return-to-duty testing is specifically for employees who are returning to work after an extended absence for any reason, but often this reason is when an employee has tested positive in a previous test and has undergone the required treatment and rehabilitation process for substance abuse. Post-rehabilitation testing or follow-up testing for rehabilitated employees can also be periodic and unpredictable, however, as determined by the organization’s drug-free workplace policy.


Blanket testing is similar to random testing in that it is unannounced and participants cannot prepare for passing a drug test by abstaining beforehand. However, instead of testing a random employee or selection of employees, all personnel are tested.


Other types of drug testing that can be included in your drug-free workplace policy are voluntary, probationary, pre-promotion, and return-after-illness testing. These are all generally announced, allowing employees to anticipate and prepare for testing, but remain effective options for employers to include in a comprehensive drug-free workplace program.

What Are the Federal Guidelines for Drug Testing and Who Must Follow Them?

Federal agencies, such as the U.S. Department of Transportation, are overseen by the Substance Abuse and Mental Health Services Administration (SAMHSA), which is part of the Department of Health and Human Services (DHHS), and are subject by law to follow their guidelines.
However, because SAMHSA’s mandatory guidelines have been supported by court decisions even in the private sector, many private employers choose to follow them as a precautionary measure even though they are granted some latitude to implement policies of their own design. Why reinvent the wheel, however, when you can stay confidently on safe legal ground by following or at least being aware of SAMHSA’s established guidelines and substance abuse regulations?
These Federal guidelines include:
  • Having test results evaluated by a qualified Medical Review Officer (MRO)
  • Requiring the use of only SAMHSA-certified drug labs
  • Provisions for the five substances (six including alcohol) tested for in Federal drug-testing programs: Amphetamines (meth, speed, crank, ecstasy), THC (cannabinoids, marijuana, hash), Cocaine (coke, crack), Opiates (heroin, opium, codeine, morphine), Phencyclidine (PCP, angel dust), and in some cases Alcohol (ethanol, ethyl alcohol, booze)
  • The required procedures to assure accuracy and validity in the testing process: Chain of Custody, Initial Screen, Confirmation Test, Split Sample.

SAMHSA’s Testing Process Procedures and Who’s Allowed to See the Results

Observing the four procedures outlined by the SAMHSA will provide the necessary quality control measures to conduct drug testing within your organization with confidence.
  • Chain of Custody: This is a form that follows and documents the life cycle of the sample, from the moment it’s collected to its disposal. This provides an unbroken link, in writing, between the specimen and the employee or applicant while the sample is being handled and stored at the collection site and the laboratory.
  • Initial Screen: This covers the sample’s first analysis, which on its own cannot be considered wholly accurate or reliable since it’s possible for an initial screen to result in a false positive. A second confirmation test is always done on a positive result at this stage.
  • Confirmation Test: This second test is performed a little differently to provide added specificity and is considered highly accurate. Its intention is to rule out any false positives from the initial screen and is performed by gas chromatography/mass spectrometry (GC/MS). The confirmation test and the initial screen must agree in order for the test results as a whole to be considered positive.
  • Split Sample: At the time the sample is collected, it is split in two—one half for the initial screen and the other for the confirmation test if the first returns positive.
  • MRO: Before the test results can be reported to the employer as positive, the results must be reviewed by an MRO, who is a licensed medical doctor with training in substance abuse. The MRO makes sure of the correct application of chain-of-custody and crosschecks with the employee or applicant to rule out the interference of certain doctor-prescribed medications, which can cause a positive result.
  • Restricted Access to Results: Employees and applicants generally must sign a release that allows the results of the drug and alcohol test to be viewed by the employer. Otherwise the result of a drug test can be considered personal health information and protected under the Health Insurance Portability and Accountability Act (HIPAA). That being said, employers must handle such information with discretion, as with all sensitive materials, regardless of whether the employee or applicant has signed a release.

Drug Testing Methods

The most common method of drug testing for the five illicit drugs listed in the SAMHSA guidelines is urinalysis, while breath testing is the most common for alcohol. Other types of bodily specimens can be collected for detecting specific types of drugs and usage, such as blood, hair, oral fluids, and sweat.
  • Urine: Shows the presence or absence of drug metabolites in urine. Metabolites are drug residues that remain in a person’s system for some time after usage, even after the effects of the drug are no longer present.
  • Breath: Measures how much alcohol is in the blood stream, called Blood Alcohol Concentration (BAC).
  • Blood: Provides a more accurate measure of how much alcohol or drugs are actively present at the time the sample is collected. The detection window, however, is shorter for blood drug and alcohol tests as opposed to urine.
  • Hair: Provides evidence of usage history of a specific drug, not current impairment, with a longer detection window going back 90 days.
  • Oral Fluids: Easy to collect and harder to adulterate, detects current use by collecting traces of drugs or alcohol in the mouth.
  • Sweat: Used mainly to maintain probation or parole compliance, signs of usage are collected with a skin patch and worn for a length of time.

Drug Test FAQs

  • What other drugs can private employers test for apart from the ones listed by the SAMHSA?

    There is an 8-panel test that includes SAMHSA’s listed substances plus Barbiturates (phenobarbital, butalbital, secobarbital, downers), Benzodiazepines (tranquilizers such as Valium, Librium, and Xanax), and Methaqualone (Quaaludes.) A 10-panel test includes all the above plus Methadone, used to treat heroin addiction, and Propoxyphene (Darvon compounds). Other substances that can be included in drug screening for employers are Hallucinogens, Inhalants, Anabolic steroids, Hydrocodone, and MDMA.

  • How long are certain substances 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
  • Who Pays for Drug Tests?
  • The employer. Additionally, under the Fair Labor Standards Act (FLSA), employees are generally paid for time spent undergoing required testing.

Starting a Drug-Testing Program

Though employers are not prohibited by any Federal laws from testing employees and applicants for drug use, it is important to become familiar with state laws that prohibit or restrict random drug testing on employees who aren’t in safety-sensitive positions. The Americans with Disabilities Act (ADA) also has protections—in certain situations—for individuals with a history of substance abuse who are considered qualified with a disability.


While drug testing is an important component of a drug-free workplace program, it’s also important to have provisions for clearly outlining your expectations regarding drug use and for uniform supervisor training on detecting signs of use and enforcing policies. It is also advisable to seek legal consultation for an existing program or before starting a new one, which will help you confidently create a comprehensive drug-free workplace program to protect your company, your employees, the people you serve, and ultimately your community.