Frequently Asked Questions
Drug Testing FAQs
Introduction: Drug Testing Facts
Prescription drug abuse is a serious problem in the U.S. The Surgeon General, as reported by NIDA, states that alcohol and drug abuse, including tobacco, costs the economy over $740 billion per year. Costs are related to crime, lost work productivity and health care.
The rate of positive pre-employment workforce drug screens and other drug use data in the general U.S. population is reported by Quest Diagnostics:
- Looking at data from close to 9.2 million urine drug tests from January to December 2022 in the general U.S. workforce, the overall rate of positive urine tests stayed steady from 4.6% (2021) to 4.6% (2022). This compares with a 13.6% positivity in 1988.
- The rate of positive tests from opiates (for hydrocodone / hydromorphone) dropped from 0.27% in 2021 to 0.24% in 2022. Oxycodone / oxymorphone also declined, from 0.20% to 0.18%.
- Marijuana positivity in the general U.S. workforce has increased by 4.7% (4.3% in 2022 compared to 4.5% in 2023), compared to 3.1% 2019. Over 5 years, positive urine drug screens for marijuana have increased 45.2%.
- In 2023, positive results resulting from post-accident marijuana urine testing in the general U.S. workforce was 7.5%, and follows an increasing trend since 2015, which shows at 114.3% increase
A pre-employment drug test is primarily limited to drugs with the potential for abuse, including some prescription drugs, and alcohol. In addition, sports drug testing is often required for college-level, professional and Olympic athletes. Illegal, recreational drugs, and performance-enhancing drugs may also be required in sports testing, such as anabolic steroids, erythropoietin, diuretics, recombinant human growth factors, and alcohol.
Pre-employment workplace drug testing usually requires the applicant to give a urine or oral saliva sample, but may also infrequently require blood, sweat, or hair.
In certain jobs, especially those that require a high level of safety, employees may be subject to random drug testing. Random drug screening may be used in instances of workplace accidents and if the employer has suspicion that the employee is abusing drugs. Random drug testing may occur without cause for suspicion depending upon company policy. States may also have laws regarding random drug testing.
Some U.S. companies may offer employee-assistance programs to support substance abuse treatment. On the other hand, some employers are not tolerant of this issue and it may result in termination from employment.
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.
Workplace drug testing involves notifying an applicant that pre-employment drug testing will need to take place as part of the application process. They may have to present to the laboratory within a specified time frame, for example within 24 hours, to lessen the chance that drugs in their system will be excreted and undetectable. Applicants are directed to a specific laboratory to submit a sample for drug screening (usually for urine test results).
Once at the facility, the applicant must submit a sample at the discretion of the laboratory personnel and in keeping with their standard policies. Hair, sweat, saliva or blood drug test samples may also be used in pre-employment drug screen, although this is not common practice.
During the laboratory evaluation, strict chain-of-custody practices and standards are followed to prevent adulteration of the sample. This legal procedure requires documentation of each person who handles the specimen through the entire phase of testing.
Certain laboratory procedures may require direct visual observation while the specimen is being voided, although this is not common. This occurs most often when the donor has previously attempted to tamper with a sample.
5 Panel Drug Test
Employers may use a standard five-panel test of "street drugs" that may include any of the following substances:
- marijuana (THC)
- cocaine
- PCP (phencyclidine)
- opiates / opioids (e.g., codeine, hydrocodone, hydromorphone, oxycodone, oxymorphone, morphine, heroin [6-acetylmorphine])
- amphetamines, methamphetamine
- MDMA (ecstasy)
10 Panel Drug Test
Some employers may elect a ten-panel drug test that also includes any of the above plus:
- methadone or other narcotic prescription drugs
- benzodiazepines (such as alprazolam, oxazepam)
- barbiturates (such as amobarbital, butalbital, pentobarbital, phenobarbital, or secobarbital)
- methaqualone (Quaaludes, no longer on US market))
- propoxyphene (Darvon, no longer on US market)
Alcohol drug testing may also occur. Other more recent designer drugs of abuse, such as Bath Salts, may be included. Which drug test is used is dependent upon the private employer, federal or state requirements, or other workplace guidelines that may be in place.
Testing for the synthetic opioid, fentanyl, is not included in the revised urine Mandatory Guidelines for Federal Workplace Drug Testing Programs, but can be tested for on a case-by-case basis.
Examples of companies that are certified (2024) to perform drug testing include:
- Quest Diagnostics Inc.
- Laboratory Corporation of America Holdings (LabCorp)
- US Army Forensic Toxicology Drug Testing Laboratory (testing for Dept. of Defense employees only)
- Alere Toxicology Services
- Clinical Reference Laboratory Inc.
Other companies that are used for federal workplace drug testing can also be found at SAMHSA.gov.
- the drug used
- a drug's half-life (the half-life is the amount of time it takes for half of a drugs concentration to be eliminated from the body. Drugs with shorter half lives are eliminated more quickly.)
- subject's state of hydration and fluid balance
- frequency of drug use
- route(s) of administration
- cut-off concentration used by the testing lab to detect the drug.
| Drug | Class | Street Name | Prescription Brand Name Examples | Detection Time in Urine |
| Amphetamine | Stimulant | speed | Dexedrine | up to 2 days |
| Barbiturates | depressants / sedatives / hypnotics | downers, barbs, reds | Fiorinal (butalbital combination) | short-acting: 2 days long-acting: 1-3 weeks |
| Benzodiazepines | depressants / sedatives / hypnotics | bennies | Ativan, Klonoin, Valium, Xanax | therapeutic dose: 3 days; chronic use: 4 to 6 weeks or longer |
| Cocaine (benzoyl ecgonine metabolite) | Stimulant | coke, crack, rock cocaine | N/A | cocaine urine test: up to 4 days |
| Codeine | Analgesic / Opiate | N/A | N/A | 2 days |
| Dextroamphetamine | Stimulant | N/A | Xelstrym, Zenzedi | up to 3 days |
| Ethyl alcohol, ethanol | Depressants / Sedatives / Hypnotics | alcohol, liquor, beer, wine, booze | N/A | urine: 1 to 12 hours serum/plasma: 1 to 12 hours |
| Heroin | Analgesic / Opiate | smack, tar, chasing the tiger | N/A | 2 days |
| Marijuana, THC, cannabidiol | Hallucinogen | pot, dope, weed, hash, hemp | Marinol, Syndros, Cesamet, Epidiolex | single use: 2 to 7 days prolonged use: 1 to 2 months |
| Methadone | Analgesic / Opiate | fizzies | Methadose | 3 days |
| Methamphetamine | Stimulant | speed, ice, crystal, crank | Desoxyn | up to 2 days |
| Methaqualone | Depressants / Sedatives / Hypnotics | ludes, disco bisquits, 714, lemmons | Quaalude | up to 14 days |
| MDMA (methylenedioxy-methamphetamine) | Stimulant | Ecstasy, XTC, ADAM, lover's speed | N/A | up to 2 days |
| Morphine | Analgesic / Opiate | N/A | Duramorph PF, Kadian, MS Contin | 2 days |
| Phencyclidine | Hallucinogen | PCP, angel dust | N/A | 14 days, up to 30 days in chronic users |
| Propoxyphene | Analgesic / Opiate | N/A | Darvocet, Darvon | 6 hours to 2 days |
Some employees may ask does alcohol show up on a drug test? Alcohol has a short half-life in the urine. A urine drug test for alcohol may detect alcohol for 2 to 12 hours.
Results from workplace drug testing are fairly quick and can usually be received in a few days. An employer may also request to have the test done with a rapid test that can provide results on the same day. Negative results are usually received within 24 hours; however, a positive screen will require further testing that may take a few days up to one week.
If the initial screen is negative, a medical review officer (MRO) will typically contact the employer with the results. If a positive result occurs, a MRO will contact the applicant for further questioning. It is important to notify the laboratory or MRO of any medications currently in use, including prescription, over-the-counter or herbal medications. The applicant may have to provide proof of a valid prescription and prescriber information for prescription medications.
A concern for anyone undergoing drug testing is the possibility of a false positive result. Initial screening drugs tests may infrequently result in false positive results, although confirmatory (GC-MS or LC-MS) testing greatly lessens the chances of a false positive - reducing the risk to close to zero.
It is important that a person undergoing drug testing complete an accurate history of all prescription, OTC, and herbal drug use prior to the time of the sample collection.
Certain substances, over-the-counter (OTC) or prescription drugs may result in false positives due to cross-reactivity with other substances, although many assays have been reformulated to avoid these possibilities. For example, decongestants like ephedrine have been implicated in causing false positives for amphetamines.
- Poppy seeds and dextromethorphan have been reported to lead to a false positive result for opiates. Poppy seeds may cause a false positive for morphine and dextromethorphan for phencyclidine (PCP). Some tests may be set at levels that will not detect morphine from food consumption, such as with poppy seeds bagels or rolls.
- The body metabolizes codeine to morphine and both substances may be found upon testing.
If benzoylecgonine, the main metabolite of cocaine is detected, the person cannot claim that the result is a false positive due to Novocaine or any other "-caine" type of drug. Benzoylecgonine is only found in nature as a metabolite of cocaine, and there would be no other valid reason for it to be present in a drug screen.
Confirmatory testing with GC-MS or LC-MS will identify individual drugs or metabolites in a sample, and almost eliminate the chance for a false positive result.
"Passive" smoke inhalation from being in a room with people smoking marijuana is not considered a valid excuse, as the cut-off concentrations for lab analysis are set well above that which might occur for passive inhalation.
Other abnormalities in the urine screen may indicate that results may be a false negative or that there was deliberate adulteration on the sample. For example:
- A low creatinine lab value can indicate that a urine sample was tampered with -- either the subject diluted their urine by consuming excessive water just prior to testing or water was added to the urine sample. To help avoid this problem, the testing lab may color the water in their toilet blue to prevent the sample being diluted with water from the toilet.
- Creatinine levels are often used in conjunction with specific gravity to determine if samples have been diluted.
- Subjects may also attempt to add certain enzymes to the urine sample to affect stability, but this often changes the pH, which is also a tested parameter.
All of these variables, and others, are looked at in the lab analysis.
In some labs, patients who receive a positive result may have the option to pay for an independent retest of the urine sample that was originally submitted. A new urine sample is not allowed for the retest as the drug in question may have been excreted from the body by that time.
The results of drug testing should remain confidential and kept separate from the regular employee work file.
Cannabidiol (CBD), one of the components found in cannabis, has been more frequently used in the U.S. since the government lifted a restriction on growing hemp. Licensed farmers can now grow hemp, as long as it contains less than 0.3% THC. Hemp is a cannabis plant that has little tetrahydrocannabinol (THC) in its make-up. THC is the chemical in marijuana that leads to the "high".
CBD is promoted to help with conditions like pain, insomnia, and anxiety. Today, you can find CBD in everything from massage oil extracts, to skin lotions, to gummy bears, and it is easily accessible online or at stores. It is also the primary ingredient in the prescription medication Epidiolex, used to treat seizures in people with Lennox-Gastaut syndrome or Dravet syndrome.
People who are using CBD may wonder if it can affect their drug test? Researchers have found that pure CBD did not cause a false-positive on two commercial drug tests used in the U.S. However, because these products are not regulated by the FDA, they may not always be pure, which could lead to variable results.
A recent study found that 20% of CBD products (1 in 5) were contaminated with THC. Another cannabis compound known as cannabinol (CBN) did react with the drug tests, as it is a tetrahydrocannabinol (THC) derivative.
Bottom line: even if your drug test turned up a false-positive for CBD, a confirmatory test would be used to distinguish CBD from other compounds. However, if your CBD product was contaminated with THC, your confirmatory test may have a positive result.
Yes. Rules vary from state to state where marijuana is now legal for recreational or medical use. Also, as marijuana can stay in the system for a long period of time, the employee may use marijuana legally, but be drug tested at a later time and test positive.
In general, marijuana legalization laws in states where it is legal support employers in drug testing for marijuana use and firing people for it. Marijuana use is still illegal under federal law, and many employers prefer to maintain their drug-free workplace policies. It is still classified as a Schedule I drug under federal law.
However, laws are changing, and some states such as Maine, Arizona, and Minnesota have enacted employee protections. As each state has their own set of laws, it's usually best to seek legal advice to discuss specific marijuana testing laws prior to employment.
In April 2024, the DEA proposed to reschedule marijuana from Schedule I to III under the Controlled Substances Act (CSA). Schedule I drugs are defined as those that have a high potential for abuse and no currently accepted medical use in the United States.
Goals of federal rescheduling may be to allow for greater medicinal use of THC products like marijuana with a legally written prescription and easier access for research studies. But if rescheduling were to occur without other legislative amendments, state-level recreational or medical marijuana use would still remain illegal under federal law.
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