There are a number of factors that affect the detection rate of substances in urine and blood. These include the type of test used, the dose taken, the user’s tolerance level, the potency of the substance, the metabolism of the user, and the existence of any underlying medical conditions.
- Methamphetamine and Benzodiazepine can be detected in urine up to 6 days after ingesting
- LSD has a short half-life, meaning it stops being detectable in blood in as little as three hours
- Hair testing works by segmenting the hair into different sections for analysis. one month of hair growth usually equates to 1cm and this is how the analysis is broken down
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Why do people need drug tests?
There are multiple reasons why toxicology tests, commonly referred to as drug tests, are required. The most predominant use of drug tests occurs in legal settings, such as for probation meetings, court cases, custody hearings, divorce proceedings, and other scenarios whereby an individual will need to prove their sobriety.
Other instances where drug tests may be needed include the workplace; especially in careers where being intoxicated on the job can be dangerous.[1] Also, many athletes and sporting professionals will need to complete drug tests in order to prove they are not doping to get ahead of the competition. Occasionally, schools and other educational institutes will require students and faculty to perform drug tests, though there is some ethical debate around testing children.
Different types of drug tests
There are four primary methods of drug testing, some of which are faster but less accurate, and others that require more rigorous lab analysis. Breath testing is occasionally used for alcohol detection, especially in instances of drunk driving, but doesn’t have the same accuracy as other methods. The four types of drug tests are:
Urine testing
Urine testing is the common form of substance detection test as it is affordable, easy, and offers quick results. It can detect if substances have been in the system up to a few days after use and is the only approved method for federally mandated testing.[2]
Blood testing
Blood testing takes longer to process than urine but is more effective and accurate at detecting concentrations of substances. Substances leave the bloodstream a lot faster than they do from other parts of the body, meaning testing is usually only accurate if substances have been used within 72 hours of testing.[3]
Saliva testing
Saliva is one of the weakest methods of toxicology testing, as chemicals and hormones used to detect drugs and alcohol only stay in saliva for a few hours to a couple of days.
Hair testing
Hair testing is used to assess drug history for up to a period of one year and is extremely accurate. Hair testing works by segmenting the hair into different sections for analysis. one month of hair growth usually equates to 1cm and this is how the analysis is broken down. For example, 6cm of hair equals 6 months of consumption data. This data is so accurate that it can determine whether someone has been around marijuana smoke or smoked the drug directly. [4]
Hair strand drug testing works by looking for the metabolites (chemical signatures) of the substances that are absorbed into the blood and deposited into the hair as a result of drug consumption. This is a much more accurate test of consumption than follicle analysis as it highlights usage directly in a specific timeframe as opposed to contamination.[4]
What determines how long drugs stay in your system for?
There are many factors that influence how long drugs and alcohol stay in the system, most of which are unique to the individual, and some to a particular substance being detected. These include:
- Metabolism
- Height
- Weight
- Gender
- Ethnicity
- BMI
- The type of drug used
- Quantity of drugs used
- How frequently they were used
- The drug's half-life
- Dehydration levels
- Medical history
- Polydrug use
How long do substances stay in your system?
Below is the average detection time for substances, broken down by urine, blood, saliva, and hair. Note; these times are an average and are not universally accurate for every person.
How long does alcohol stay in your system?
To find out more, read our guide to how long alcohol stays in your system.
How long does marijuana stay in your system?
| Test type | Time period |
| Urine | Up to 30 days |
| Blood | Up to 4 hours |
| Hair | Up to 90 days |
| Saliva | Up to 72 hours |
Related blog: How Long Does Cannabis (THC) Stay in Your System?
Related blog: How Long Does CBD Stay in Your System?
How long does synthetic marijuana stay in your system?
| Test type | Time period |
| Urine | Up to 72 hours |
| Blood | Up to 48 hours |
| Hair | Up to 90 days |
| Saliva | Up to 48 hours |
How long do Benzodiazepines stay in your system?
Benzodiazepines such as Xanax, Valium, and Ativan are sedatives that are typically prescribed for anxiety, insomnia, and some muscle disorders. Benzodiazepines stay in the system typically no longer than a week but can remain longer if abused in high amounts or for long periods of time.
How long does Librium stay in your system?
How long does Valium stay in your system?
How long does Xanax stay in your system?
Read our guide to learn more about how long Xanax stays in your system.
How long does Ativan stay in your system?
How long does Restoril stay in your system?
How long do hallucinogens stay in your system?
Hallucinogens are either man-made chemicals like Ketamine and others are naturally occurring such as psilocybin which is found in magic mushrooms. Hallucinogens are also split into two categories; dissociative drugs like PCP and classic hallucinogens like LSD. Most leave the system within a few days but like most substances can still be detected in hair follicles up to three months later.
How long does LSD (Acid) stay in your system?
| Test type | Time period |
| Urine | Up to 4 days |
| Blood | Up to 12 hours |
| Hair | Up to 90 days |
| Saliva | N/A |
How long do magic mushrooms (Psilocybin) stay in your system?
Read here to find out more about how long magic mushrooms stay in your system.
How long does Ketamine stay in your system?
| Test type | Time period |
| Urine | Up to 11 days |
| Blood | Up to 4 days |
| Hair | Up to 90 days |
| Saliva | N/A |
How long does PCP stay in your system?
How long does Mescaline stay in your system?
| Test type | Time period |
| Urine | Up to 3 days |
| Blood | Up to 24 hours |
| Hair | Up to 90 days |
| Saliva | Up to 10 days |
Related: How long does Peyote last?
How long do opioids stay in your system?
The opioid drug class encompasses a wide range of chemical makeups and functions. Therefore, each type of opioid or opiate drug stays in the system for a different amount of time. Commonly abused prescription opioids include Tramadol, Oxycodone, Codeine, and Hydrocodone. The rise in synthetic opioids like Fentanyl has a direct link to the rising number of opioid-related overdoses in the United States due to its wide availability and high potency.
How long does Tramadol stay in your system?
| Test type | Time period |
| Urine | Up to 72 hours |
| Blood | Up to 48 hours |
| Hair | Up to 6 months |
| Saliva | Up to 48 hours |
Find out more here: How long does Tramadol stay in your system?
How long does Oxycodone stay in your system?
How long does Heroin stay in your system?
| Test type | Time period |
| Urine | Up to 3 days |
| Blood | Up to 6 hours |
| Hair | Up to 90 days |
| Saliva | Up to 1 hour |
How long does Fentanyl stay in your system?
How long does Hydrocodone stay in your system?
How long does Codeine stay in your system?
Find out more here about how long codeine stays in your system.
How long does Morphine stay in your system?
| Test type | Time period |
| Urine | Up to 3 days |
| Blood | Up to 3 days |
| Hair | Up to 90 days |
| Saliva | Up to 3 days |
Related: Morphine versus other opioids
How long does Methadone stay in your system?
How long does Vicodin stay in your system?
How long do stimulants stay in your system?
Stimulant abuse occurs when people misuse prescription medications such as Ritalin and Adderall as well as illicit substances like meth and cocaine. MDMA (ecstasy and molly) is technically a stimulant but also produces hallucinogenic effects.
How long does Adderall stay in your system?
Read here to find out more about how long Adderall stays in your system.
How long does MDMA stay in your system?
Related: How long does ecstasy, molly, and MDMA stay in your system?
How long does Ritalin (Methylphenidate) stay in your system?
| Test type | Time period |
| Urine | Up to 2 days |
| Blood | Up to 12 hours |
| Hair | Up to 90 days |
| Saliva | Up to 2 days |
How long do inhalants stay in your system?
Compared with other drugs, inhalants such as aerosols, industrial cleaners, and whippet canisters have incredibly short half-lives. Most of these substances will have left the system in a matter of minutes, making them very hard to detect with standard drug tests.
Inhalants are predominantly abused by teens and young people which can increase the half-life of inhalants like nitrates due to their fast metabolism. Abusing inhalants like whippets also affects the brain and puts young people at risk as their brains have yet to develop fully.
Other substances
There are many drugs that fall outside of the standard list of substances that are tested for. Some of these other drugs may not be tested for legal reasons, such as if your doctor or a medical professional needs to see how long a particular medication has been in the system so they can give accurate diagnoses and prescriptions. Some common other drugs tested include:
How long do Barbiturates stay in your system?
How long does Gabapentin stay in your system?
How long does Flexeril stay in your system?
| Test type | Time period |
| Urine | Up to 13 days |
| Blood | Up to 3 days |
| Hair | Up to 90 days |
| Saliva | Up to 36 hours |
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