Different substances can be detected in the system for varying amounts of time, depending on the drug and what part of the body is being tested.
If you have an upcoming drug test, the pressure of passing it can feel overwhelming — especially if you have a history of substance use. Knowing how drugs are detected in the body can help you determine how likely it is that a drug test will be positive. However, it’s important to understand that feeling stressed about a drug test can be a sign that you are struggling with substance use and may need help to stop.
How Are Drugs Detected in the Body?
Drugs can be detected in the body through drug tests. Most commonly, a doctor orders a drug test; however, they can also be ordered by employers and other organizations. Not all drug tests are the same, though. Some drug tests look for specific substances, while others scan for a broad array of substances. Some drug tests will look for drugs in your blood, while others will detect blood in your urine, saliva and even your hair.
Different Drugs Take Different Amounts of Time to Process
Each drug acts differently in your system, and your body can take varying amounts of time to process different drugs. This is not only true of different categories of drugs — such as alcohol and benzos — but also of different agents within each category. For example, certain benzos may take longer for your body to process than other benzos. The time it takes for the body to process substances depends on the specific drug, as well as individual factors like liver and kidney function and overall health.
How Long Drugs Are in Your System
- Methadone Hydrochloride
- Morphine Sulfate
How Long Do Drugs Stay in Your Urine?
Drugs can be detectable in urine for hours or days, depending on the drug. Urine drug tests are among the most common types of tests because they are easy and non-invasive to administer. For example, urine tests can be given by a person with limited or no medical training, unlike blood tests. The urine sample can then be brought to a lab where it can be analyzed by experts.
Alcohol can be found in your urine for about 80 hours. The most common type of alcohol urine test is the EtG (ethyl glucuronide) test. EtG is a byproduct that is created when the liver breaks down alcohol.
Marijuana can be detected in your urine for 30 to 45 days after the last use. If you use weed heavily or have used it over a long period of time, it may show up in your urine for longer than someone who has just used it once or twice.
Opioids and Opiates
Opioids and opiates are commonly detected in urine, but the amount of time they are detectable can vary depending on the exact drug. This is because opioids break down in the body at different rates. Some opioids pass through the system unchanged and are found in the urine, while others must first be broken down to other substances. The detection times for some common opioids include:
- Heroin: Up to two days
- Fentanyl: Between eight and 24 hours
- Oxycodone (OxyContin): Between three and four days
- Hydrocodone (Vicodin): Between one and three days
Urine tests are commonly conducted to screen for benzos. However, not all benzos are created equal, as some may stay in the body for longer than others. This means that some may be detectable in the urine for longer than others. The amount of time that common benzos can be found in urine includes:
- Lorazepam (Ativan): Between three and six days
- Clonazepam (Klonopin): Up to four days
- Alprazolam (Xanax): Between five and seven days
- Diazepam (Valium): Up to seven days
Urine tests for cocaine generally look for the breakdown product benzoylecgonine (BE) because it lasts longer in the system than cocaine itself. BE can generally be found in urine for up to five days.
Urine tests are a common way to test for meth. The drug can be found in the urine for up to five days after the last use.
Drugs stay in your bloodstream for varying lengths of time. Blood tests for drugs are usually less common than urine tests. This is because blood tests are invasive and require someone who is trained to draw the blood. In addition, drugs leave the bloodstream more quickly than they leave the urine. This is due to multiple reasons that can vary based on the drug. For example, many substances stay in the bloodstream for short amounts of time and then move to other parts of the body before eventually being excreted through the urine. Still, blood tests for drugs may be used in certain cases, and it can be useful to know how long drugs can remain detectable in your bloodstream.
How Long Do Drugs Stay in Your Blood?
How long alcohol stays in your blood depends on several factors, including how many drinks you have had. Generally, your liver can process about one drink an hour. Your blood alcohol concentration (BAC) reflects this and shows how much of your blood is alcohol.
Online calculators can help you estimate your BAC based on your gender, weight and how much you have had to drink. For example, a BAC of 0.08% is the legal limit in most states, and it means that your bloodstream is 0.08% alcohol. Your body can lower your BAC by around 0.015 per hour. This means that if your BAC is 0.12%, you would need to wait about three hours for it to reach the legal limit of 0.08%.
Marijuana does not stay in the blood for long and is undetectable after around three to four hours. Marijuana blood tests are uncommon because there is only a narrow window of opportunity to draw blood for a drug test.
Opioids and Opiates
Opioids and opiates are generally not found in blood tests for as long as they are found in other tests, such as urine tests. This is because many opioids and opiates are rapidly broken down, or metabolized, into other substances. Further, many opioids and opiates do not stay in the bloodstream; instead, they rapidly move to the parts of the body where they perform their activities, such as the brain. The blood test detection times for some common opioids are:
- Heroin: A few minutes
- Fentanyl: Up to 12 hours
- Oxycodone (OxyContin): Up to 24 hours
- Hydrocodone (Vicodin): Up to a day
Benzos are generally detectable in blood tests, but the detection window for benzos in blood is shorter than it is for urine. Some benzos last longer than others in the blood, as a few can be detectable for more than a day. The blood test detection window for common benzos includes:
- Lorazepam (Ativan): Up to 16 hours
- Clonazepam (Klonopin): Up to 60 hours; its breakdown product 7-amino clonazepam can be found up to 92 hours
- Alprazolam (Xanax): Up to 27 hours
- Diazepam (Valium): Up to 37 hours
Cocaine leaves the blood quickly, so blood tests are not commonly used for cocaine. A cocaine blood test would need to be conducted within a few hours of cocaine use for the drug to show up. Since this is unlikely, urine tests or other drug tests are more commonly used.
Blood tests for meth are uncommon, but they may show if meth has been taken within the past 25 hours.
How Long Do Drugs Stay in Your Saliva?
Drugs can stay in saliva for varying amounts of time, depending on the drug. Saliva tests are a non-invasive alternative to urine tests. Unlike blood tests, they do not require extensive training to administer, so they are sometimes used to detect drugs. However, drugs typically do not stay in saliva as long as they stay in urine, making saliva tests less common than urine tests.
Alcohol can be detected in your saliva if your BAC is 0.02% or above. It can be hard to know what your BAC is, but online calculators can help you to estimate this. Since your body can lower your BAC by 0.015 per hour, you can use your estimated BAC to make an educated guess about how long alcohol would stay in your saliva. For example, if your BAC is at the legal limit of 0.08% and the burnoff rate is 0.015 per hour, it would take four hours to reach the saliva detection threshold of 0.02%.
Saliva tests can generally detect marijuana for around 24 hours after the last use.
Opioids and Opiates
Opioids and opiates can be detected with saliva tests, but urine tests remain more common. This is because the drugs are usually detectable for longer periods in urine than saliva. Saliva test detection times for some common opioids include:
- Heroin: A few minutes
- Fentanyl: From one to three days
- Oxycodone (OxyContin): Up to four days
- Hydrocodone (Vicodin): Up to two days
Benzos are detectable in saliva and can be found for varying amounts of time, depending on the test and the benzo. While some benzos can be detected for only a few hours after use, others may be detected for days or even a week. The saliva detection times of some common benzos include:
- Lorazepam (Ativan): Up to eight hours
- Clonazepam (Klonopin): Up to five days; its breakdown product 7-amino clonazepam can be found up to six days
- Alprazolam (Xanax): Up to 2.5 days
- Diazepam (Valium): Up to nine days in some tests; other labs can only detect it for up to two days
Cocaine can be detected in saliva for up to three days after the last use.
Meth can be found in saliva for up to two days following the last use of the drug.
How Long Do Drugs Stay in Your Hair?
Most drugs can be detected in the hair for up to 90 days. The hair is unique among parts of the body that can be tested for drugs. Unlike urine, blood and saliva, drugs do not temporarily deposit in hair. Instead, drugs stay in the hair for the life of the hair.
Hair drug tests do not test a long strand of hair. Instead, hair drug tests remove a 1.5-inch section of hair closest to the scalp. This amount of hair can show if there was any drug use in the past 90 days.
How Long Do Drugs Stay in Your Breast Milk?
Drugs can stay in your breast milk for hours or even days after the last use. While drug tests are usually not performed on breast milk, it is still important to know whether drugs will show up in your breast milk if you breastfeed or are planning on breastfeeding. If you take a drug — whether prescribed or illicit — and are pregnant or breastfeeding, you should inform your doctor so they can let you know if it is safe for your baby.
Alcohol can be found in breast milk for two to three hours after each drink you have had. This means that if you have had one standard drink, alcohol can be detected in your breast milk for two to three hours. However, the more you drink, the longer it might take for alcohol to be cleared from your breast milk. For example, three standard drinks might take up to eight hours to leave your breast milk.
Marijuana can be found in breast milk, but how long the drug stays detectable can vary widely. Various studies show that THC (tetrahydrocannabinol), the active ingredient in marijuana, can be detected anywhere from six hours to six weeks after the last use. This is because THC is absorbed into the body’s fat, where it slowly releases into the body and breast milk over time.
Opioids and Opiates
Opioids and opiates are often found in breast milk. Although breast milk itself is rarely tested for drugs, it is still extremely important to know if your baby will be exposed to any drugs you take if you breastfeed. Durations of common opioids in breast milk include:
- Heroin: Unknown duration in breast milk; however, women who use heroin should not breastfeed. Experts suggest pumping and discarding breast milk for 24 to 48 hours after the last use of heroin.
- Fentanyl: Unclear duration in breast milk; however, women who take fentanyl under a doctor’s orders may breastfeed, as the drug is present in very low levels in breast milk.
- Oxycodone (OxyContin): The duration of oxycodone in breast milk depends on how many doses of the drug were taken. Studies have shown that women who have taken four doses of oxycodone had the drug present in breast milk for up to four hours. Women who have taken up to 11 doses of the drug had it present in breast milk for up to 36 hours.
- Hydrocodone (Vicodin): Unclear duration in breast milk; however, this can vary based on a woman’s genetics. Some women excrete a lot of hydrocodone into their breast milk, which is likely due to their specific genes for an enzyme called CYP2D6. This enzyme breaks down hydrocodone, and some women are genetically predisposed to a more active version of the enzyme than other women. This can lead to higher than expected levels of hydrocodone in breast milk.
Although benzos can be found in breast milk, little data exists on how long they stay in milk. When taken as prescribed at recommended doses, some benzos can be used while breastfeeding. Recommendations about commonly used benzos include:
- Lorazepam (Ativan): Unclear how long it stays in milk, but no special precautions are needed in breastfeeding infants.
- Clonazepam (Klonopin): Unclear how long it remains in milk. It can be used cautiously while breastfeeding, but other benzos are preferred.
- Alprazolam (Xanax): Unclear how long it stays in milk; other benzos are preferred in breastfeeding women.
- Diazepam (Valium): Unclear how long it stays in milk, but experts recommend waiting six to eight hours after a dose to breastfeed.
Cocaine can stay in breast milk for up to 36 hours after the last use. However, cocaine is often contaminated with other substances, and some of them may stay in your breast milk even longer. It is important to avoid breastfeeding if you take an illicit substance like cocaine.
It is important not to breastfeed if you use meth. Meth remains in breast milk for as long as 72 hours after the last use, but the exact amount of time can vary. A mother who has used meth should wait between 48 to 100 hours after the last use to breastfeed unless a urine screen shows there is no meth in the system.
Influencing Factors for How Long Drugs Stay in Your System
Even if two different people take the exact same drug at the same time, the drug may be detectable in their bodies for different periods of time. This is because drug detection depends on not only the drug itself, but also individual factors for each person. The combination of drug-dependent and person-dependent factors is what causes a drug to last for longer or shorter periods in a person’s system. Some common influencing factors for how long a drug stays in your body include:
A drug’s half-life refers to how long it takes for half of a dose to be cleared from your body. Each drug has a different half-life. Some substances may have a half-life that lasts only a few minutes, while others may have a half-life of several hours. It takes five half-lives to completely clear a drug from your system. This means that drugs with longer half-lives will take considerably longer to leave your body than drugs with shorter half-lives.
Dosage and Frequency of Use
If you take a drug frequently or in large doses, there is a higher chance that it will build up in your system. This is especially true of drugs that tend to deposit in the body’s fat, such as cannabis. If you take a high dose of a drug for a long period of time and use the drug frequently, it may take much longer to leave your system than if you infrequently use small doses over a short period of time.
Liver and Kidney Function
Most drugs are broken down by liver enzymes and leave the body through the urine. This means that a healthy liver and kidneys are important for a drug to leave your system quickly. Liver or kidney impairment can make a drug stick around in your system for much longer than expected.
Age, gender and ethnicity can all play a role in how long a drug stays in your system. Drugs tend to linger for longer periods in the bodies of older adults, especially if they have underlying health or kidney problems. Gender can also play a role, as male bodies can process substances like alcohol more quickly than female ones. Lastly, ethnicity can also influence how long a drug stays in your system, as some genetic traits are more common in certain ethnic populations. Ethnic differences in genes for the enzymes that help the body break down substances can mean that substances may last longer in the bodies of people from one ethnicity versus another.
Weight can indirectly play a role in how long it takes a drug to leave your system. Some substances accumulate in body fat, meaning that a heavier person may end up storing a higher proportion of the drug in their body than a lighter person. This means that the drug would leave the body of a heavier person more slowly in some cases.
Types of Drug Tests and What They’re Used For
Multiple types of drug tests exist and can be used for different things. For example, some drug tests are more commonly used for employment screenings. The number of drugs tested corresponds with the number of the drug’s “panel.” For example, this means that a 4-panel drug test checks for the presence of four drugs.
It is important to remember that specific drugs included in the tests can vary. A 4-panel drug test means that the test is looking for four drugs; however, which specific drugs are included in the test is left up to the organization requesting the test and may vary.
Common examples of what substances these drug tests look for and why include:
4-Panel Drug Test
Tests for: Various drugs; may include cocaine, amphetamines (including methamphetamine), opioids/opiates and phencyclidine (PCP)
Common uses: Because 4-panel drug tests often exclude marijuana, they may be used for workplace drug tests in states where marijuana is legalized or the employer does not elect to screen for marijuana use.
5-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), cocaine, marijuana, opioids/opiates and phencyclidine (PCP)
Common uses: This is the most common workplace drug test, and it is also used by the federal government and truck drivers.
6-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates (or sometimes benzodiazepines), cocaine, marijuana, opioids/opiates and phencyclidine (PCP)
Common uses: This is often used in workplace drug testing when the employer wants to add a barbiturate or benzodiazepine drug screen. Employers who require employees to use heavy machinery may want to screen for these drugs, as they are sedatives and can make the job more dangerous.
7-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates, benzodiazepines, cocaine, marijuana, opioids/opiates and phencyclidine (PCP)
Common uses: This is often used in workplace drug testing when the employer wants to add both a barbiturate and a benzodiazepine screen to the standard 5-panel drug test. This can include employers who require the use of heavy machinery.
8-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates, benzodiazepines, cocaine, marijuana, opioids/opiates, phencyclidine (PCP) and quaaludes
Common uses: This is used when workplace drug testing for quaaludes is desired. As quaaludes have become less common in North America, this drug test is not performed as frequently as before.
9-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates, benzodiazepines, cocaine, marijuana, opioids/opiates, phencyclidine (PCP), propoxyphene and quaaludes
Common uses: This is used in workplace drug tests when the employer wants to add on a specific test for the opioid propoxyphene (Darvon). This drug was also previously sold in combination with acetaminophen under the brand name Darvocet. As propoxyphene was removed from the United States market in 2010, this drug test is less common.
10-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates, benzodiazepines, cocaine, marijuana, methadone, opioids/opiates, phencyclidine (PCP), propoxyphene and quaaludes
Common uses: This is used in workplace drug testing when the employer wants to add on a specific test for methadone, which is not picked up in standard urine opioid drug screens. This test is most commonly used for civil servants and people in law enforcement or the medical field. It can also be used to see whether a person is violating the terms of their probation.
11-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates, benzodiazepines, cocaine, marijuana, methadone, opioids/opiates, oxycodone, phencyclidine (PCP), quaaludes and tricyclic antidepressants
Common uses: This is used in workplace drug testing when the employer desires an 8-panel drug test but also wants to screen for tricyclic antidepressants and the opioids methadone and oxycodone, which do not show up in standard opioid urine drug screens. Tricyclic antidepressants are less commonly prescribed in the United States but include drugs like amitriptyline and nortriptyline.
12-Panel Drug Test
Tests for: Amphetamines (including methamphetamine), barbiturates, benzodiazepines, cocaine, ecstasy (MDMA), marijuana, methadone, opioids/opiates, oxycodone, phencyclidine (PCP), propoxyphene and quaaludes
Common uses: This is the most comprehensive urine drug test and can be used in workplaces where the employee has a significant level of responsibility.
Commonly Asked Questions About How Long Drugs Stay in Your System
Do Drug Tests Test for Alcohol?
Alcohol is not included on many standard drug panel screens. However, employers can test for it separately. In addition, an employer may ask a lab for a custom panel. Custom panels may screen for alcohol on a drug panel screen, so although it is less common, it is possible that a drug panel may test for alcohol.
How Accurate Are At-Home Drug Tests?
Home drug tests are FDA-approved and are fairly accurate. Home tests show that a substance is present, but not how much of it. In addition, false positives are possible; for example, eating poppy seeds can cause a false positive for opioids/opiates on a drug screen. For this reason, positive home drug tests should be sent to a laboratory for more intensive follow-up testing. The lab will be able to confirm or negate the presence of illicit substances in the drug test.
What Drugs Don’t Show Up on a Drug Test?
Drug tests can be conducted for nearly any substance. Even drug panel tests can be customized by an employer or organization to look for a specific substance that other employers do not screen for. That said, some drugs are less likely to show up on standard drug tests than others. For example, urine screening for party drugs like ketamine is less common than screening for amphetamines or opioids/opiates.
Drug and Alcohol Withdrawal Can Kill You
If you have an upcoming drug test and are concerned it might show evidence of your substance use, it can be tempting to quit the substance cold turkey and hope for the best. However, for many substances, this can be very dangerous. For example, if you drink heavily or use benzodiazepines, withdrawal symptoms can be dangerous and even fatal in some cases.
The best and safest way to stop heavy substance use is to speak with your doctor. They may recommend a medically supervised detox to help wean you safely off the substance. In an inpatient medical detox setting, you are under round-the-clock care from doctors and nurses as your body is slowly weaned off the substance. Medical detox helps you stop substance use, and it is followed by rehab to help keep you off substances for good. In a rehab setting, you undergo therapy to explore why you began to rely on substances in the first place and begin to develop coping strategies for staying substance-free over the long term.
Getting Help for Drug and Alcohol Addiction
If you or a loved one struggles with drug or alcohol addiction, an upcoming drug test can serve as a wake-up call that you need help. Fortunately, professional support is available at The Recovery Village. Contact our intake experts today to learn how we can help you begin the journey to a healthier, substance-free life in recovery.
Bowling Green State University. “Alcohol Metabolism.” October 16, 2019. Accessed July 3, 2022.
Thokala, Madhusudhana Rao; Dorankula, Shyam Prasad Reddy; Muddana, Keertrthi; Velidandla, Surekha Reddy. “Alcohol Saliva Strip Test.” Journal of Clinical and Diagnostic Research, March 15, 2014. Accessed July 3, 2022.
Calculator.net. “Blood Alcohol Concentration (BAC) Calculator.” Accessed July 3, 2022.
Centers for Disease Control and Prevention. “Alcohol.” February 9, 2021. Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Fentanyl.” May 15, 2022. Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Hydrocodone.” October 23, 2019. Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Oxycodone.” February 15, 2021. Accessed July 3, 2022.
Oelhaf, Robert C.; Azadfard, Mohammadreza. “Heroin Toxicity.” StatPearls, May 19, 2021. Accessed July 3, 2022.
Bartholomew, Marguerite Lisa; Lee, Men-Jean. “Substance use in the breastfeeding woman.” Contemporary OB/GYN, September 13, 2019. Accessed July 3, 2022.
Nordal, Kristin; Øiestad, Elisabeth L.; Enger, Asle; et al. “Detection Times of Diazepam, Clonazepam,[…]Repeated Drug Intake.” Therapeutic Drug Monitoring, August 2015. Accessed July 3, 2022.
ARUP Laboratories. “Drug Plasma Half-Life and Urine Detection Window.” October 2021. Accessed July 3, 2022.
Food and Drug Administration. “Drugs of Abuse Home Use Test.” September 27, 2018. Accessed July 3, 2022.
elSohly, H.N., elSohly, M.A., Stanford, D.F. “Poppy seed ingestion and opiates urinalysis: a closer look.” Journal of Analytical Toxicology, October 1990. Accessed July 3, 2022.
Mobile Health. “What Drug Panel Should I Choose?” Accessed July 3, 2022.
Food and Drug Administration. “FDA Drug Safety Communication: FDA recom[…]use of propoxyphene.” February 7, 2018. Accessed July 3, 2022.
Mobile Health. “What are the different drug panels?” Accessed July 3, 2022.
Mobile Health. “5 Panel Drug Test.” Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Lorazepam.” June 21, 2021. Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Clonazepam.” August 16, 2021. Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Alprazolam.” April 18, 2022. Accessed July 3, 2022.
Drugs and Lactation Database (LactMed). “Diazepam.” February 15, 2021. Accessed July 3, 2022.
ARUP Laboratories. “Therapeutic Drug Monitoring.” June 2021. Accessed July 3, 2022.
ARUP Laboratories. “Drug Plasma Half-Life and Urine Detection Window.” October 2021. Accessed July 3, 2022.
Gryczynski, Jan; Schwartz, Robert P.; Mitchell, Shannon D.; et al. “Hair Drug Testing Results and Self-repor[…]isk Illicit Drug Use.” Drug and Alcohol Dependence, May 17, 2014. Accessed July 3, 2022.
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