How to Beat a Drug Test in 2025

Drug testing from the patient's standpoint can be stressful. "Is that one bong rip still in my system?" That's not what we're covering here. We're talking about what it looks like from the drug tester's perspective.

Step one: Make sure the sample is labelled with two unique patient identifiers.

Drug testing, from a medical laboratory standpoint, is a structured and scientifically rigorous process designed to detect the presence of illicit substances, prescription medications, or their metabolites in a biological specimen. But it's not foolproof and drugs are not always detectable. The goal may be clinical diagnosis, treatment monitoring, employment screening, legal investigation, or forensic assessment. The process requires careful specimen handling, validated analytical methods, and stringent quality controls to ensure reliable and legally defensible results (if that's the goal).

Specimen Types

Urine. The most common testing method, by far, is urine collection into a cup. This will be the preferred method for most ER patients, outpatient (or court ordered) drug testing, and professional monitoring programs (for some federal workers and transportation workers). Generally, a few mLs are required. And often, it only takes a few drops. Urine remains the predominant specimen in workplace and outpatient settings due to its non-invasive collection, higher drug concentrations, and longer detection window for many substances.

Blood. The second most commonly tested sample type is blood. Blood is typically reserved for situations requiring assessment of recent use or intoxication, such as emergency department or impaired driving cases. Also, blood can be used to test for less common drugs and for quantitative results (rather than the common urine tests, which are usually qualitative - yes or no).

Other... Other rarely tested specimens for drugs include oral fluid (saliva), hair, sweat, and, in some cases, meconium or umbilical cord tissue in newborns. Oral fluid testing offers a compromise between invasiveness and detection of recent use. Hair and sweat are used less frequently but offer long-term usage profiles or continuous exposure detection.

Day of the party. It was only second-hand smoke, right?

What Tests are Covered in the most Common Drug Screens

Urine drug screens typically run in the ER setting cover generally used (or abused) drugs and will give a POSITIVE or NEGATIVE result. They can then be sent out for qualitative results if desired for any reason (generally not done).

Here is an example of a commonly used test in ERs, the MedTox 13 test system. Also included are the thresholds for detection, below which concentrations, the drug will not be detected. In other words, the drug might be present, but not in high enough concentration to read as a positive.

Amphetamine - 500 ng/mL

Barbiturates - 200 ng/mL

Benzodiazepines - 150 ng/mL

Buprenorphine - 10 ng/mL

Cocaine - 150 ng/mL

Methamphetamine - 500 ng/mL

Methadone - 200 ng/mL

Opiates - 100 ng/mL

Oxycodone - 100 ng/mL

Phencyclidine (PCP) - 25 ng/mL

Propoxyphene - 200 ng/mL

Cannabinoids (THC) - 50 ng/mL

Tricyclic Antidepressants (TCA) - 300 ng/mL

You might be asking about Fentanyl, the big bad drug du jour. While in the opioid class, fentanyl is generally not detected by drug screen such as these and will need to be tested for separately if not included by name. This is because the test is for opiate metabolites, which fentanyl produces very little of.

"How Long are the Windows of Detection for These Drugs?"

Cannabinoids (Marijuana, THC)

Delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, is rapidly metabolized in the liver to 11-nor-9-carboxy-THC (THC-COOH), the primary urinary metabolite. THC-COOH is highly lipophilic and is stored in fat tissue, leading to prolonged excretion in urine—often several days to weeks after use in chronic users. This makes cannabinoid detection especially sensitive to frequency of use and body fat content. But if you rarely smoke, you'll probably be clean within one week.

Cocaine

Cocaine is metabolized primarily into benzoylecgonine, which is the principal compound detected in urine testing. Benzoylecgonine can typically be found in urine within hours of use and may remain detectable for up to three days in occasional users. Heavy or chronic users may show positive results for several days longer due to accumulation and slower clearance.

Opiates

Natural opiates such as morphine and codeine, as well as semi-synthetic opioids like hydrocodone and oxycodone, are excreted largely in urine. For heroin users, the key urinary marker is 6-monoacetylmorphine (6-MAM), a unique metabolite of heroin that confirms heroin use specifically, although it is only detectable for a short window (often less than 24 hours). Morphine itself can be a metabolite of either heroin or codeine, and codeine is sometimes partially metabolized into morphine. Laboratories often report both substances to clarify potential sources.

Amphetamines and Methamphetamines

Amphetamines are water-soluble and largely excreted unchanged in urine, which makes them readily detectable. Methamphetamine is similarly excreted, although it may also be metabolized to amphetamine. Because many over-the-counter medications can cause false positives on initial screening tests, confirmatory testing is essential to distinguish illicit methamphetamine from legal ephedrine- or pseudoephedrine-based products.

Phencyclidine (PCP)

Phencyclidine is absorbed rapidly and metabolized by the liver, but a significant proportion of it remains unchanged and is excreted in urine. Because PCP is lipophilic, it can accumulate in the body with chronic use, extending the detection period. It may be found in urine up to eight days after a single use, and longer in heavy users.

Benzodiazepines

Benzodiazepines are metabolized into a variety of compounds depending on the specific drug. Diazepam, for example, is broken down into nordiazepam, temazepam, and oxazepam, all of which can be measured in urine. The detection window varies significantly across different benzodiazepines due to their half-lives and metabolic pathways. Long-acting benzodiazepines can be detectable for days to over a week, while short-acting ones may only be detectable for one to two days.

Barbiturates

These central nervous system depressants are generally classified by their duration of action. Short-acting barbiturates, such as secobarbital, may be detectable in urine for one to two days, whereas long-acting ones like phenobarbital can be detected for up to three weeks. Barbiturates are excreted both unchanged and as metabolites, which laboratories can detect with high specificity.

Synthetic Opioids (e.g., Fentanyl, Methadone)

Standard immunoassay panels may not reliably detect synthetic opioids like fentanyl, which are structurally dissimilar to morphine. For fentanyl, urine testing targets the metabolite norfentanyl. Methadone is detectable directly and is often measured alongside its metabolite EDDP (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine) to confirm compliance with treatment regimens or identify abuse.

The day after the party.

Legal Samples

For a drug test sample (urine or blood) to be legally admissible in court, it must have what's called a "chain of custody." That means there must be a written record of everyone who has handled samples or been involved in the collection of a sample and how it was collected. For instance, what was used to clean the phlebotomy site... if it was alcohol, then the value is no good. Local police departments will usually have a form they want you to use with these samples, such as legal alcohol blood draws. Any mistakes on this form and lead to a case being thrown out.

Urine Drug Sample Collection: Laboratory Best Practices

Urine sample collection for drug testing is a carefully standardized process that ensures specimen integrity, accurate results, and legal defensibility. Whether used in clinical, occupational, forensic, or compliance settings, proper collection techniques are essential to prevent adulteration, contamination, or substitution. The process is governed by best practices laid out by organizations such as the Substance Abuse and Mental Health Services Administration (SAMHSA), the Department of Transportation (DOT), and Clinical Laboratory Improvement Amendments (CLIA) for laboratory testing in the United States.

Patient Preparation and Verification. The first step in urine drug collection is patient identification and verification. The collector must confirm the identity of the donor using a government-issued photo ID or other accepted method. The collector explains the procedure, answers questions, and ensures that the donor understands their rights and responsibilities during the process. The donor is then asked to remove bulky clothing and empty their pockets. Personal belongings are either secured in a designated area or handed to a supervisor to prevent the introduction of adulterants or substitution materials.

Specimen Collection Procedure. The donor is provided with a sterile, tamper-evident collection cup, typically pre-labeled with the necessary information, including the donor’s name or identifier, date, time of collection, and collector’s initials. In most standard settings, the collection is unobserved, though direct observation may be required in certain legal or compliance situations (e.g., return-to-duty testing, suspected tampering, or prior failed tests).

The restroom used for collection is secured to eliminate sources of adulteration. The water supply may be turned off or dyed blue, soap dispensers may be sealed or removed, and the toilet tank may be taped. The collector waits outside the restroom while the donor provides the specimen. For typical drug testing, a minimum of 30 mL of urine is required, with larger volumes preferred to allow for split specimen testing if needed.

Labeling and Chain of Custody. The collector transfers the urine into two tamper-proof containers labeled “primary” and “split” specimens, if applicable. The containers are sealed with evidence tape or tamper-evident seals, and the labels are signed or initialed by both the collector and the donor to confirm accurate identification.

Chain of Custody (if needed). A chain-of-custody (COC) form is completed, documenting each step in the handling and transfer of the specimen. This form includes the donor’s demographic information, reason for testing, type of test ordered, time of collection, and each person who handles the specimen thereafter. The donor is asked to certify the specimen was provided voluntarily and is their own.

CLIA Regulations

The regulations for drug collection are pretty simple for non-legal samples. Often, tests are CLIA-waived or moderate complexity. And for most labs, anything beyond the drug screens will be sent out for further testing.