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What shows up on a 12 panel drug test?

A 12 panel drug test is a urine screen that looks for 12 of the most commonly abused substances. It provides more comprehensive results than a 5 or 10 panel drug test and is commonly used for employment screening and probation monitoring.

What Drugs Are Tested For In A 12 Panel Test?

A standard 12 panel drug test looks for the following substances:

  • Amphetamines – amphetamine, methamphetamine
  • Barbiturates – amobarbital, butalbital, pentobarbital, phenobarbital, secobarbital
  • Benzodiazepines – alprazolam, clonazepam, diazepam, lorazepam, midazolam, triazolam
  • Cocaine
  • Marijuana
  • Methadone
  • Methaqualone
  • Opiates – codeine, heroin, morphine
  • Phencyclidine (PCP)
  • Propoxyphene
  • MDMA (Ecstasy)
  • Oxycodone

How Long Do Drugs Show Up On A 12 Panel Test?

How long a drug remains detectable in urine depends on several factors including the frequency of use, metabolism, dosage, and body mass. Here is a general overview of detection times for the substances tested in a 12 panel drug screen:


Amphetamine: 1-2 days
Methamphetamine: 2-4 days

Amphetamines are metabolized quickly, so are generally only detectable for 1-4 days after last use. However, heavy or chronic use can extend detection times.


Short-acting (e.g. secobarbital): 1 day
Intermediate-acting (e.g. amobarbital): 2-3 days
Long-acting (e.g. phenobarbital): 2-3 weeks

Barbiturates have varying detection times depending on how quickly they are metabolized. Shorter-acting ones clear in 1-3 days while long-acting can be detectable for 2-3 weeks.


Alprazolam: 3 days
Clonazepam: 2-4 days
Diazepam: 4 days
Lorazepam: 4 days

Most benzodiazepines remain detectable for 1-4 days after last dose. Diazepam and lorazepam tend to stay in the system slightly longer. Chronic use can extend detection times.


2-4 days

Cocaine and its metabolites are generally detectable for 2-4 days after use. Detection time can increase with heavy, repeated use.


Casual use: 3 days
Moderate use: 5-7 days
Heavy use: 10-15 days
Chronic use: 30+ days

Marijuana has an extended detection window because THC is fat soluble and accumulates in body tissues. For infrequent users, it can be detected for up to 3 days. In heavy users, it may be detectable for over a month after last use.


2-4 days

Methadone has a relatively short detection time of around 2-4 days. However, metabolites may be detectable for 1-2 weeks in some cases.


7-14 days

Methaqualone has a detection window of approximately 1-2 weeks. Higher doses or chronic use can extend the detection period.


Codeine: 1-2 days
Heroin: 1-2 days
Morphine: 2-4 days

Opiates like heroin and morphine are rapidly metabolized and excreted from the body. They are generally detectable for 1-4 days after last dose.


1 week

PCP is detectable in urine for approximately 3-7 days after use. Metabolites may remain for 2-3 weeks in chronic users.


1-2 days

Propoxyphene has a short detection time window of around 1-2 days. Higher doses may extend the detection period slightly.

MDMA (Ecstasy)

1-3 days

MDMA is detectable for 1-3 days after using. Higher or repeated doses can increase the detection window to 4-5 days.


1-4 days

Oxycodone can be detected for 1-4 days after last use. Chronic users may test positive for 5 days or longer.

Can You Beat A 12 Panel Drug Test?

It is very difficult to cheat or beat a comprehensive 12 panel drug test. Since it screens for a wide range of substances, dilution techniques or adding adulterants are unlikely to produce a false negative. The most reliable way to pass is to abstain from all detectable substances for a sufficient period of time. For heavy marijuana users, this may mean detoxing for up to 6 weeks before testing.

Here are some common methods people try to pass a 12 panel drug test and their likelihood of success:


Diluting urine by drinking a lot of fluids can help lower drug concentrations. However, most labs check for diluted samples and may require a retest. Taking creatine or vitamin B supplements can help mask dilution but isn’t foolproof.

Likelihood of beating test: Low


Adulterants like bleach, vinegar, eye drops or ammonia can interfere with screening results when added directly to urine samples. However, labs check samples for adulteration and tampering.

Likelihood of beating test: Low


Substituting clean urine from someone else is risky but can work if fresh and at body temperature. Labs sometimes check for substituted samples.

Likelihood of beating test: Moderate

Detox drinks

Detox drinks claim to flush out drug metabolites but effectiveness is questionable. More reliable options include heavily diluting urine or using synthetic urine.

Likelihood of beating test: Low

Synthetic urine

Pre-mixed synthetic urine can be substituted for real urine. Brands like Quick Fix contain uric acid and other markers to evade detection. Proper heating and concealment are critical.

Likelihood of beating test: Moderate to High

How Accurate Are 12 Panel Drug Tests?

Twelve panel drug screens are highly accurate when performed correctly by a certified lab. The initial screening uses immunoassay testing which is sensitive for detecting trace levels of drugs and metabolites. Any non-negatives are then confirmed through more specific GC/MS testing. This 2-step method provides an accuracy rate of approximately 98-99%.

False positives are unlikely with the level of confirmation testing done in labs. However, false negatives can sometimes occur from:

– Diluted urine samples
– Low drug concentrations
– Poor quality tests
– Improper testing procedures

To ensure accuracy, urine samples should be collected properly, stored at consistent temperatures, and tested within a reasonable timeframe using certified procedures. Proper abstinence from drugs prior to testing is critical for avoiding true positive results.

Who Orders 12 Panel Drug Tests?

Twelve panel drug screens are most often ordered by:

  • Employers – for pre-employment, random, or reasonable suspicion testing
  • Courts/probation officers – for those on probation or parole
  • Drug treatment programs – to monitor patients in recovery
  • Government agencies – for safety-sensitive positions requiring drug screening
  • Schools/athletics – to deter drug use by students and athletes
  • Parents – concerned about possible drug use by teens and children

The extensive screening provided by a 12 panel test deters people from using multiple illegal or prescription drugs not detectable in a standard 5 panel test. However, the costly lab testing means it is not used for general workplace screening as often as a 5 panel.

What happens if you fail a 12 panel drug test?

Failing a 12 panel drug test can have serious consequences depending on the reason for screening. These may include:

  • – Loss of a job opportunity for workplace testing
  • – Probation violation or criminal charges for court-ordered testing
  • – Suspension or loss of athletic eligibility for school testing
  • – Expulsion from a drug treatment program
  • – Loss of visitation rights or custody of children for parents

Those who fail an employment-related test are unlikely to be considered for similar jobs requiring drug screening. People on probation may face steep penalties like incarceration or added restrictions.

However, retesting is sometimes allowed after a failed drug test. People also have the right to contest results by requesting a reanalysis of the original sample or submission of a new sample. This can identify any potential testing errors. Though false positives are rare with GC/MS confirmation testing.

Does everyone get the same 12 panel drug test?

While the 12 substances tested for are fairly standard, drug screens can vary slightly based on the ordering entity. For example:

– Employers may customize panels to test for specific drugs commonly misused in their industry. A construction company could test for synthetic opioids while a transportation company checks for PCP.

– Probation programs work with courts to include drugs relevant to the person’s background and offense. This provides targeted screening.

– Drug treatment facilities may remove certain substances like benzodiazepines or methadone from screening if they are part of the individual’s prescribed treatment plan.

So while the typical 12 panel will include the core drugs outlined earlier, there is some flexibility based on the entry and objective of testing. The most accurate approach is to avoid illicit use of any substance for which testing is a possibility.


A 12 panel drug test provides comprehensive screening that goes beyond a standard 5 panel test. It detects a wide range of commonly abused prescription, illegal, and over-the-counter substances through an accurate and extensive testing process. Staying completely drug-free is the only foolproof way to pass a 12 panel urine drug screen. While there are ways some try to beat the tests, these carry significant risks and often fail. Given the severe consequences of a positive test, avoiding illegal and non-medical drug use is critical for anyone being screened through a professional lab’s 12 panel protocol.