29 Jun How long do drugs stay in urine?
Urine-based drug tests are among the most popular options for toxicology screenings, offering a fast, easy, and accessible way to test for the most common forms of addictive drugs. Frequently required for everything from job applications to medical school admissions, urine tests are standard and expected in a wide range of circumstances.
However, urine test results aren’t always as clear-cut as they seem. Due to the significant differences in various forms of common drugs, drugs can stay in the urine for varying amounts of time and thus are measured using different cutoffs.
Metrics for Drug Testing
So, if you do drugs, will they appear in a urine drug panel? Maybe. But maybe not.
The reality of drug testing exists on a spectrum. Tests, including urine tests, operate on a threshold basis: too much causes a positive result, while too little results in a negative one. This cutoff level is determined by the lab testing the specimen and is specifically determined for each individual drug rather than all drugs at once. There is a standard set by SAMHSA, but the precision of the testing may vary.
In urine toxicology tests, drug presence in the body is measured in nanograms per milliliter (ng/ml). A nanogram is the equivalent of one-billionth of a gram, which is just thirty-five thousandths of an ounce. In essence, this measurement indicates that drug panels screen for extremely small amounts of drug metabolites within the urine. With such low thresholds, even casual or first-time users may fail drug tests if samples are collected in a timely manner.
It should also be noted the processing of specimen can vary depending on the workflow. For some settings, it may be appropriate to use a ’12-panel cup’, which tests the urine right in the cup, without being sent off to a lab. These cups can detect multiple substances and report which substance has been triggered. Some settings may use this cup exclusively while others send it off for confirmatory testing. Generally, testing for background checks will send specimens directly to a reference lab for a wider panel of definitive testing.
Variables Affecting Drug Testing
Most drug test takers believe that time is the only factor that affects drug test results. This, however, is not the case. In reality, numerous elements can play into the results of a urine test, from weight to metabolism.
How much water do you regularly drink? If the answer is “a lot” – or, alternately, “a little” – your hydration could easily affect the outcome of a drug test. For some drugs, regular hydration can dilute urine to the point that drugs are less detectable, minimizing the likelihood of a positive result. Although, this can set off triggers from other metrics to invalidate the test.
Larger individuals with a high body mass are often more likely to test positive for drugs. This isn’t because obesity or an overweight BMI creates confusion with known substances; rather, chemical compounds derived from drugs last longer in fatty tissue, creating an extended time period in which drugs can be detected.
Frequency of Use
The frequency of use can often play a role in the detection of drugs within the body. While some substances metabolize at roughly the same rate regardless of use, like cocaine, others, like marijuana, may differ based on usage patterns. In the case of marijuana, the chemical THC can remain in the fatty tissue for extended periods of time and may be detectable for several weeks or even up to a month in heavy users. For first-time users, however, traces of marijuana may leave the body in as little as a day or two.
Time of Use
As all drug users are well aware, drug metabolites remain in the body for varying lengths of time. Some substances, like benzodiazepines, can stay in the body for three to six weeks, while other drugs, like LSD, can be out of the system in a matter of 24 hours. Regular users often attempt to time drug tests around these common benchmarks to avoid detection.
In testing for drugs, several other factors can play a role in a positive test, including:
- The pH of urine; the more acidic urine is, the shorter the detection time
- Individual metabolism; those with a fast metabolism will likely process drugs faster than average
- Tolerance; those with a high tolerance to a particular substance often metabolize doses quicker
- There are more elements to a specimen measured than the ‘panel’ of substances being screened including nitrite, specific gravity, and as mentioned pH. These details mean that a very complete picture of the patient’s body is created, making it very difficult to ‘dupe’ the drug test.
Common Cutoffs for Frequently-Used Drugs
Under Federal guidelines, the results of a drug test must pass through two cutoff levels for positive detection. If a test reflects a limit above the initial cutoff, a confirmation test is performed at a lower threshold to corroborate these results. A test is assumed negative if the primary cutoff is not achieved; in these cases, no confirmation testing is required.
Measurable cutoff levels vary from drug to drug. SAMHSA, the Substance Abuse and Mental Health Services Administration, dictates testing cutoffs for both initial and confirmatory testing. The substances covered by SAMHSA’s guidelines – marijuana, cocaine, opiates, phencyclidine, and amphetamines – are what is known as the “SAMHSA Five,” and are considered the five most common substances for testing. While some prescription drugs, like prescriptions opiates, are included in these basic panels, other forms of prescription medications, like barbiturates, often are not. However, more complex drug panels are becoming increasingly common, especially as the science behind testing improves.
More comprehensive drug panels may include:
- Barbiturates, like phenobarbital, butalbital, and secobarbital – 2 to 4 days in urine
- Benzodiazepines, like Valium and Xanax – 3 to 6 weeks in urine
- Ethanol, like alcohol – 3 to 5 days in urine
- Hallucinogens, like LSD and mushrooms – 1 to 3 days in urine
- Inhalants, like glue, paint, and hairspray – several hours in urine
- Anabolic steroids – 3 weeks to 6 months in urine, based on method of ingestion
Furthermore, testing does not just include the ‘substance ingested’ but panels may also include metabolites produced by the body from the substance. For example, ‘cocaine’, the substance as we know it, can be absorbed to levels below 1 ng/ml within 24 hours. As it is metabolized benzoylegonine became high in concentration as well as norcocaine, m-hydroxycocaine and p-hydroxycocaine, and others. So, testing for cocaine may not be practical, as it would not be detected, but panels are made up of combinations of metabolites that are the result of drug use.
Initial Cutoff Levels
Initial drug cutoff levels (known as screening, often triggered by a urine cup) are intended to be a primary benchmark upon which substance test results can be measured. These thresholds are essentially a baseline and are generally greater than or equal to confirmatory testing levels.
|Substance||Cutoff Level (ng/ml)||Duration in body (urine test)|
|Marijuana metabolites||50||3 days to 3 weeks|
|Cocaine metabolites||150||3 to 4 days|
|Opiate metabolites||2000||3 to 4 days|
|Phencyclidine||25||7 to 14 days|
|Amphetamines||500||3 to 6 days|
Mandatory Guidelines for Federal Workplace Drug Testing Programs
Confirmatory Cutoff Levels
Confirmatory testing often utilizes lower thresholds to determine use, and can vary from one substance to another within a particular class of drugs.
|Substance||Cutoff Level (ng/ml)|
Mandatory Guidelines for Federal Workplace Drug Testing Programs
Cheating the System
Unfortunately, as long as drug use remains normalized in American society, users will attempt to get around the system. Entire online communities are dedicated to evasion of drug tests, providing tips to beat toxicology screenings that range from drinking excessive water to utilizing synthetic urine. Common techniques for cheating urine tests include:
- Attempting to flush the digestive system with water, cranberry juice, vinegar, or other beverages
- Utilization of synthetic urine
- Purchase of urine from a non-user
- Dilution of urine samples with water or chemical additives
- Complex devices to store and keep substitute urine warm
Despite the frequency with which users employ underhanded tactics to avoid detection, these techniques to pass drug tests are generally not effective. While flushing the system may reduce the presence of drugs in the body, this is a gamble; at worst, levels will still be above the initial cutoffs. The use of synthetic urine or dilution agents is almost always detectable, leading to test results that indicate signs of tampering. There are multiple metrics measured aside from ‘drug panels’ applied to the specimen that detect abnormalities.
Legality of Fraudulent Testing
While it is not technically illegal to cheat on a drug test, the response can be severe. The U.S. Department of Transportation, for example, requires those who are caught tampering with samples to be fired immediately, regardless of actual test results. In many other fields, this is also the case; most companies do not want to employ someone who cheats on a test. In a parole situation, falsifying results can be enough to lead to a revocation of rights, and an evaded pre-employment screen can cause a job offer to be withdrawn. With few benefits to be had and risks that outweigh rewards, cheating on a drug test is not a suggested path for those undergoing drug tests. States are also making moves to ban fake urine that is used to cheat tests.
Using Oral Swabs to Reduce Tampering
Due to the nature of urine samples, privacy is often granted during collection. This provides substantial opportunity for participants to smuggle in fake or altered urine and other tools to cheat the system, utilizing workarounds while alone in the bathroom.
Oral swab testing can reduce the likelihood of cheating or fraud; with samples taken in the presence of a tester from the inside of the mouth, there is virtually no way to alter the saliva itself. This provides a greater level of confidence in testing results, ensuring accurate responses and a significantly reduced risk of fraud.
At Captiva Lab, we advocate the use of oral swabs as an alternative to many drug testing scenarios. Our pioneering oral fluid testing method ensures greater accuracy and reliability, virtually eliminating common cheating methods and providing results that practitioners and healthcare professionals can trust. Please contact Captiva Lab today to learn more.