Imagine stumbling into one of these predicaments: You arrive at work to find a stern-looking grouch in a white lab coat holding out a clear plastic cup. During a seemingly routine traffic stop, a police officer asks to swab your cheek. After spotting a series of ill-timed Instagram posts, your boss asks for a hair sample.
If you’ve recently used THC or CBD, these situations could be harmless—or devastating. Cannabis law is rapidly changing, and the uncertainty is frustrating. There are significant variances in regulation and enforcement at federal, state, and local levels, and legislators and businesses are struggling to create uniform standards that balance safety and civil liberties.
That’s why every cannabis fan should understand his or her exposure at work, school, and on local roads. What follows is a brief overview of today’s drug-testing landscape.
Who Tests, and Why
There are good reasons for drug laws. We want to protect school children from drunken bus drivers and prevent the intoxicated operation of heavy machinery and firearms. But society is now grappling with the grey-green areas created by cannabis. Let’s say you’re legally using medical marijuana in your off-hours to treat the side effects of chemotherapy; is it fair that you could be terminated by your employer if you show up clear-headed but test positive?
Fair or not, drug testing is a pre-condition of employment in certain occupations. Transportation workers may be subject to saliva, urine, blood, or hair-follicle tests. Until recently, road maintenance workers were only tested by the Federal Railroad Administration (FRA) for alcohol or drugs in the unfortunate event an employee died as the result of an on-the-job accident. Now, however, they're subject to mandatory testing, including pre-employment, random, post-accident, and reasonable suspicion.
Similar protocols apply in the military, security, energy, law enforcement, and pharmaceutical sectors. Many government contractors maintain drug-free workplaces for legal, safety, and insurance reasons and prohibit substances in Schedules I through V of the Controlled Substances Act. This includes medical marijuana.
Whether you’re working in one of these industries or not, cannabis users are wise to read the fine print in any hiring agreement or employee handbook. Once you’re on board, you’ve agreed to your employer’s terms, and courts tend to protect those agreements. You’ll have little to no legal recourse if asked to take a drug test or found to have a banned substance in your system, even if it’s legal where you live.
Signs of Change
A few cities, including Boulder, CO, and New York City (starting May 2020), prohibit many employers from testing prospective employees for marijuana use. Legal analysts expect this trend to increase, albeit slowly, because businesses pay lower workers’ compensation and disability insurance premiums when they test.
The American Civil Liberties Union has been busy protecting workers’ and drivers’ rights by trying to assure drug tests are administered in a manner consistent with the Constitution. One focus is the efficacy of saliva tests, which only detect the presence of drugs in a person’s system. Unlike breathalyzers, they don’t indicate actual impairment. Vermont’s legislature has prevented police from conducting warrantless oral fluids tests but other states, including California, Michigan, Colorado, Kansas, and Illinois, are considering pilot programs of road saliva testing. (The National Highway Traffic Safety Administration has yet to establish that saliva test devices are accurate or reliable.)
Saliva swabs and other simplified drug tests pose serious due-process and equal-protection concerns. Roadside stops are considered seizures under the Fourth Amendment, and not all stops are legitimate. Roadside tests also result in disparate treatment, especially with positive results for commonly prescribed medications such as antidepressants. And there’s the matter of racial injustice: Between 2001 and 2010, a person of color was almost four times more likely to be arrested for marijuana possession than a white person despite comparable rates of use.
Can you refuse a saliva test if you’re stopped on the road? In some places, yes, but in others, you may wind up behind bars. It pays to know the regulations and ramifications where you live and work—and to conduct some sober evaluation of your personal risk tolerance. Bottom line: Given all of the legal vagaries, the only risk-free approach right now is abstinence. Just another sign that the green revolution is closer to its schizophrenic beginning than its tolerant conclusion.
What If You’re Tested?
Your chances of testing positive for THC hinge on a variety of factors, such as the product consumed, the recency of use, the dose and duration, your body chemistry and metabolism, and the type and sensitivity of the drug test. If your job depends on zero presence of THC, be certain that your product is absolutely THC-free. According to the Substance Abuse and Mental Health Services Administration (SAMHSA), a user would test positive for THC if there are 50 nanograms of THC per milliliter in their sample. Different testing methods show positives at different rates, including as low as 15 nanograms per milliliter.
For CBD users, THC can show up in a test when the manufacturer hasn’t fully processed the hemp oil. In general, experts say that broad spectrum and isolate CBD products are safer than full spectrum. They shouldn’t contain detectable levels of THC, provided the manufacturer used proper protocols and testing. To lower the odds of a positive, stick with manufacturers that have a Certificate of Analysis (COA) displaying results of testing for THC and CBD.
With marijuana products, positive results depend on the type of test—urine, saliva or hair—and variables such as weight, body fat, metabolism, and frequency-of-use. Tests for marijuana identify THC and its metabolites as the marker for cannabis consumption. As for CBD, in theory, pure oil used in medical marijuana would not lead to a positive drug test, but that depends on whether the manufacturer thoroughly removed THC. (Urine tests are capable of detecting the drug for up to 13 days.)
Your method of consumption matters. Because most drug tests don’t just scan for the drug but also its metabolites, ingestion makes THC easier to detect for longer. When inhaled, either in vapor or smoke form, THC enters the bloodstream via absorption through the lungs, traveling straight to the heart and then through the whole body. The effects will fade quickly, but THC may be detectable in the body for weeks.
In contrast, when cannabis is ingested, THC enters the bloodstream through the stomach walls and intestines, then it travels to the liver, where it is absorbed in your gastrointestinal tract. From there, it makes its way to the heart and is circulated to the brain. Since the factors that impact detection vary greatly for each individual, there are no definitive guidelines for how long you can test positive.
Urine test: THC appears within 2-5 hours of use. A one-time user may show positive for 1-6 days; moderate user for 7–13; frequent user for 15 or more; heavy user for 30 or more; some heavy users have reported being positive 45–90 days after quitting.
Saliva test: THC appears within one hour of use and may be detected for about 12 hours after your last use.
Hair follicle test: THC will appear about 5-7 days after use and be detectable for 90 days.
Can I Test Myself?
If you’re nervous about getting nailed, you can take a practice test to see how you’ll fare. Oral and urine dip kit tests are inexpensive, especially if you only want to test for THC, and may be purchased online or over-the-counter for under $10. Two commonly available options are QuickScreen and MD Saliva Screen.