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What is a False Negative on a Drug Test?

False Negative Drug Test Result

Most people are familiar with false positives on drug tests, but are unaware of false negatives. What is a false negative on a drug test, what can you do to prevent them and what should you do if you identify one?

What is a False Negative Drug Test?

A false negative is any time that under normal circumstances a drug test would be positive for an individual but for some reason results are negative. An example would be a patient that is prescribed Oxycodone that takes his medication consistently as prescribed, but has a negative drug test during his doctor visit.

In most cases this is caused by the patient either purposefully or accidentally altering their urine sample. The most common false negative drug test is due to water loading.

False Negatives From Water Loading & Adulteration

Water loading is the process where a person drinks an excessive amount of water prior to giving a sample. Urine that is clear with no yellow tint is usually indicative of water loading. You will need to perform separate adulterant tests for Creatinine, pH and protein levels to prove that a test has been diluted by a subject ingesting excessive amounts of water.


urine color drug test chart
This chart shows how shades of urine relate to dehydration. When analyzing drug test samples, some color is preferable because urine that is completely clear cannot be distinguished from water without further testing.


Without adulteration testing pure water will show negative on a drug test assay because the tests are only meant to detect the presence of a certain drug or metabolite in a substance, not to detect if the substance is a valid sample. Subjects can simply add water to their urine, but to fool a witness they will ingest an excessive amount of water to dilute the urine that comes from their own body.

There are several products available that claim to help users pass urine drug screens. These products range from nothing more than fortified tea that dilutes your urine to products that claim to seal in fat cells for several hours. Many of these products will speed up the timeframe which a person can pass a urine screen even if it’s for no more reason than they’ve diluted their urine.

Improper Drug Test Selection

A mistake made by organizations conducting drug tests is improper test selection. Every organization will have their own considerations when choosing a testing device, but some drug tests will not detect every illicit substance that people assume.

Semi-Synthetic Opiates

Many times a doctor prescribes their patient oxycodone or another semi-synthetic opiate, but uses a 5 panel drug test that only has a test for opiates. The doctor has seen positive tests for opiates from his patients that are prescribed oxycodone, but his new patient tests negative. One study found that oxycodone was detected in 12% of opiate immunoassay tests, and many other synthetic or semi-synthetic opiates also require a special test for accurate results. 


Most assays for benzodiazepines detect their presence in the urine by testing for nordiazepam and oxazepam, the main metabolites of most benzodiazepines. Agents that follow a different metabolic pathway, such as triazolam, alprazolam, clonazepam, and lorazepam, have poor cross-reactivity with the assay due to the absence of these metabolites and thus frequently produce false-negative results. Some doctors prescribe diazepam, oxazepam, and temazepam instead to reduce lab confirmations.

False Negatives From Very High Cutoff Levels

If your drug tests have high cutoff levels it is more likely for a user that has recently ingested drugs to produce a negative result.

The National Institute of Drug Abuse and the Substance Abuse and Mental Health Services Administration publish recommended cutoff levels for drug testing which most companies follow. Dozens of other federal agencies publish their own standard cutoffs (everyone from the Department of Transportation to the Nuclear Regulatory Commission) that are usually based off federal recommendations.

Even though the federal government publishes their own guidelines laboratories and manufacturers can create products that use whatever cutoff level they deem appropriate and the federal guidelines do change from time to time.

For example opiates and morphine have two widely used cutoff levels since the early 2000s because so many people were failing employment tests because the popularity of poppy seed muffins. The recommendation soared from 300ng/ml to 2000 ng/ml. The majority of tests will use this recommendation to stay compliant with as many federal regulations as possible, but the high sensitivity tests are still available.


Poppy Seed Muffin
Poppy seed muffins caused so many false positives in the 1990s that the NIDA introduced a new cutoff level for Opiates.


In practice there is no right answer. Some regions may have popular restaurants that sell poppy seed muffins, and some industries may have a high percentage of clients that anticipate testing and use gray-hat adulteration methods to get their levels under the cutoff.

Human Error

We advertise our drug tests as being 99% accurate, but in any situation that involves a human there is a possibility of introducing human error. A technician could mislabel tags, forget to confirm the temperauture on a sample or give a patient an opportunity to switch out a sample altogether.

Human error is even more likely in a laboratory where a technician has to prepare an assay, control variables, process and record information and interpret results. Never count out human error entirely and implement procedures that can help reduce the likelihood of human error.

Faulty Device

Since the consequences of a failed drug test can be so severe t here is a great deal of work and investment that goes into quality control for drug test devices. Still there are always some faulty tests or batches of tests that slip through.

If you have several tests in a row give unexpected results you should consider that the tests may be faulty. It’s very cheap and easy to use a 2nd drug test if a subject says that their results aren’t accurate.

Our drug test cups are designed to alert the user when there is a problem with the device itself. The control line can alert you to tampering, a faulty test and some forms of improper collection.


invalid drug test result
Any test that does not show a control line is invalid and can indicate anything from a faulty test to tampering.


Keep in mind that a 12 panel drug test is actually 12 individual tests; most of the time a faulty device means only one of the strips is faulty. A certain percentage of faulty tests is expected in this industry, which is why we offer a 100% satisfaction guarantee that covers any faulty devices and any additional tests you use to troubleshoot a possible faulty test.

Other Anomolies

There are times when all of the devices are functioning properly, everyone did everything they were supposed to do and a sample is valid in every way and still there is a false negative drug test result.

The Hook Effect

One rare cause which has been addressed by manufacturers in recent years is the “hook effect” where there is so much of a drug present in the urine that there are no more binding sites left on the antibody. This can cause a lower apparent level which can lead to a negative result if it’s below the cutoff level.

Drug Degradation

One benefit of using a drug test cup is that the receptacle is also the test. There is no lapse in time between collection and testing. In a busy medical office technicians may become distracted or intentionally multi task when working on test results.

When shipping to a lab it could be even more time between collection and testing. The time in transit and any time that the shipment sits in the lab without proper refrigeration is more time for the sample to naturally degrade.

Most metabolites are stable for the short periods common in drug testing, but others are not stable especially when subjected to temperature changes or extremely high temperatures.

One example is 6-monoacetylmorphine (6-MAM), a metabolite of heroin. In the body heroin is metabolized to 6-MAM, which then metabolizes to morphine.  6-MAM lacks stability, is subject to in vitro hydrolysis and also continues to metabolize into morphine even after the urine leaves the body. One study showed that within 7 days at room temperature a urine sample that was positive for 6-MAM had hydrolyzed completely into morphine.

Limiting False Negatives on Drug Tests

Understanding that a false negative is a possibility and the likely causes is the first step in stopping them. Collecting and storing data can be an important part of investigating unexpected or suspicious results.

With enough knowledge and proper analysis many drug test results that are contradictory to expectations can be reconciled and explained. Here are some other tactics you can use to limit the likelihood of false negatives in your drug testing program.

  • Institute procedures and policies to combat water loading and adulteration
  • Use a 12 panel drug test to cover many of the synthetic and semi-synthetic opiates
  • Understand the cutoff levels and detection times for the tests you use
  • Institute policies and procedures that decrease the likelihood of human error
  • Report faulty tests to the manufacturer or retailer



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What is a False Positive on a Drug Test?

False Positive drug test

When people fail drug tests they often claim that it was faulty or there is some mistake. In most cases this is a ruse and the individual is dirty, but false positives on drug tests are real and many innocent patients have failed a drug test only to be vindicated later on by a confirmation. So what exactly is a false positive on a drug test and when is it just another attempt at subverting drug test results?

What is a False Positive on a Drug Test?

A false positive is a drug test result that is not accurate due to another substance mimicking the target metabolite.

The majority of false positives are caused by medications, foods, and supplements that are well known to cause false readings on a drug test.

Some people have gotten a false positive from second hand marijuana smoke. The most common false positives are for benzodiazepines, amphetamine, methamphetamine, marijuana and opiates.

A presentation given at the American Psychiatric Association’s annual meeting in 2010 by a researcher at the VA Medical Center in Black Hills South Dakota, Dwight Smith,  5 to 10 percent of all drug tests result in false positives and 10 to 15 percent result in false negatives.

My anecdotal research at a healthcare facility where I tested hundreds of patients each month did not support these high numbers, but we did experience a 1 to 3 percent occurrence of false positives.


CBD products come in many varieties, some have had all traces of THC removed entirely and some have not.


Most studies show that second hand smoke from marijuana and crack cocaine do not cause false positives but there have been anecdotal cases. The growing popularity of CBD products and confusion about which products contain trace amounts of THC have cause some false positives.

Many drugs have multiple identified metabolites and different immunoassays and equipment use different technologies to bind antibodies. The regeants in multi-drug test cups are generally the most stable and prominent metabolites of each drug.

Some substances will cause a false positive on a specific test under specific circumstances, but will show as negative when retested for different metabolites or using different equipment.

Legitimate false positives are rare unless a patient is prescribed a drug that is well known for causing false positives.

What Should testing Programs Do About False Positives?

Always acquire a thorough list of all the patient’s prescription, over the counter and herbal medications prior to testing. Interview the patient to find out if they drink energy drinks or eat any products that are known to cause a false positive.

Discuss adherence to medications and instruct them about how much water to ingest prior to testing to keep from diluting a sample.

A good practice is to ask an individual that just failed a drug test if they are positive for the substance. Encourage an honest answer and let them know that lying about it will only damage their desired outcome. Many people will admit to a mistake.

Always send contested drug test results to a lab for confirmation. Let the individual know that their sample will be sent to a lab that can confirm exactly what substance triggered the positive result.


Lab Drug Testing Instrument
This Gas Chromatography / Mass Spectrometry instrument combines the two techniques to give the most accurate analysis of a urine sample. By Polimerek – Own work, CC BY-SA 4.0,


When you receive the results back schedule a consultation with the individual and give them another chance to admit to their drug use before revealing the lab results.

Many courts have started programs where criminals that are alcoholic are given home incarceration on non-violent charges if they install a phone that has a breathalyzer built in. Probationers and prisoners that sign up for these programs agree that even if a positive reading comes from using mouth wash that is doesn’t matter and they will be violated as an offence.

A lot of our customers send all positive tests to a lab for confirmation, but also make decisions for care and treatment based on the results of the instant drug test.

Always instruct your clients that false positives are treated as a failed test until a lab returns the confirmation results and it is their responsibility to educate themselves about substances that could possibly affect their test results.

What is The Most Common False Positive on a Drug test?

The most common false positive in drug testing is amphetamine and methamphetamine caused by other stimulants. PCP, THC, and benzodiazepines are also common false positives. There are many substances that can interfere with the enzymes used in immunoassay drug tests when ingested in large quantities.

Things That Can Cause a False Positive on a Drug Test

One study found adulteration from household cleaning products H202 and Joy detergent caused false positives for benzodiazepines and sodium bicarbonate caused extremely high pH levels.

One study found that gentle baby soaps Johnson &Johnson, CVS Nighttime Baby Bath, Aveeno Soothing Relief Creamy Wash, and J&J Bedtime Bath caused false positives for THC for infants being tested due to their mother’s suspected drug use.

Since drug testing is used so frequently in so many applications many organizations conduct studies about false positives. Still there are so many substances humans ingest and interact with that we couldn’t possibly identify them all.

Below is a list of medications and other substances that are known to cause false positives in urine drug screens. Some will often cause an inaccurate result while others almost never do.

Once a possible cross contamination is identified use multiple confirmation methods and research the history of that medication in causing false positives. Most of these medications were identified through scientific research, but a few are from anecdotal observations at medical facilities.

What will mess up a urine test?

A few things can mess up a urine test, the most common is over dilution from drinking too much water. Other things like poppy seeds, over-the-counter medications, and certain types of CBD therapies will cause false positives.

Most drug tests are 95%-99% accurate, and aren’t affected by false positives.

Marijuana (THC) False Positives

In a study conducted to find if second-hand marijuana smoke would cause a false positive 3 non-smokers were exposed to 8 marijuana smokers who smoked 32 joints in total in a 10×10×8-ft enclosed room. No samples from the nonsmokers exceeded the federal mandated threshold. However marijuana has increased in potency since this study.

The metabolite of THC is metabolite 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH). Even though excessive intake of several substances have caused a false positive for THC, the only drug that is likely to cause a false positive is Efavirenz (Sustiva). Other known false positives are very unlikely.

  • Ibuprofen (Study)
  • Hemp Seeds
  • Efavirenz (EFV, Sustiva)
  • Ibuprofen
  • Naproxen
  • Niflumic Acid
  • PPIs (Omeprazole)

Cocaine False Positives

In a study to find if being exposed freebase crack cocaine vapors would cause a false positive, 6 volunteers in an 8×8×7-ft enclosed room were exposed to 200 mg freebase cocaine vapor; none of their urine samples exceeded the federal threshold.

Individuals that work in a jobs such as law enforcement and medicine that handle cocaine are at risk for testing positive. Cocaine can be absorbed through the skin.

A study of crime lab technicians showed 33% of subjects tested positive after analyzing solid dosage forms of cocaine. Levels in two criminologists working with large amounts of cocaine in a small room were measured up to 278 ng/mL when wearing a face mask and gloves and up to 1,570 ng/mL when wearing gloves only.


Half Kilo Cocaine
Crime labs sometimes process vast amounts of cocaine. Samples are taken from several locations of a brick to confirm the composition and purity of the evidence.


In a study of physicians administering cocaine to a patients, one physician in the group not wearing gloves had a positive test with 53 ng/mL of the cocaine metabolite in his test eight hours following exposure. Results were negative in the group wearing gloves. Another physician in this study was asked to handle cocaine for two minutes and wait 15 minutes before hand washing every two hours. This physician had a positive test of 245 ng/mL 18 hours after exposure.

Many public surfaces have been shown to be contaminated with cocaine. An analysis of 234 banknotes from 18 different US cities found that 90% contained traces of cocaine. 85% of bills in Canada had traces of cocaine and 80% of bills from Brazil. They contained up to 2,350 micrograms.

Scientific studies have found no evidence that Lidocaine or norlidocaine can cause a false positive on standard cocaine tests, but there is anecdotal evidence it is possible.

Opiates False Positives

In 1998, the federal government increased the threshold defining a positive screen for urine morphine and codeine from 300 to 2000 ng/mL to reduce spurious reports of opiate-positive tests from poppy seed consumption.

Synthetic and semi-synthetic opiates are sometimes detected in an opiate drug test, but sometimes are not. One study found that oxycodone was detected in 12% of opiate immunoassay tests.

Given this inconsistency separate tests have been developed for semi-synthetic opiates oxycodone, hydromorphone, oxymorphone, levorphanol, buprenorphine and synthetic opiates fentanyl, methadone, propoxyphene, meperidine, tramadol, pentazocine. The most common pharmaceutical opiates are included in some multi panel tests while others must be performed separate.


Poppy Seed Muffin
Poppy seed muffins caused so many false positives in the 1990s that the NIDA introduced a new cutoff level for Opiates.


  • Poppy Seeds
  • Codeine
  • Dextromethorphan (Robitussin, Delsym)
  • Dihydrocodeine
  • Diphenhydramine (Benadryl, Advil PM)
  • Levofloxacine
  • Ofloxacine
  • Naloxone
  • Pentazocine
  • Quetiapine
  • Rifampicin
  • Doxylamine
  • Fluoroquinolone

Methadone False Positives

  • Tapentadol
  • Verapamil
  • Cyamemazine
  • Creatinine
  • Doxylamine
  • Quetiapine (Seroquel)
  • Thioridazine
  • Diphenhydramine
  • Clomipramine
  • Chlorpromazine
  • Levomepromazine

Buprenorphine False Positives

  • Codeine
  • dihydrocodeine
  • Amisulpride and sulpiride

Benzodiazepines False Positives

  • Oxaprozin (Study)
  • Sertraline (Zoloft)
  • Efavirenz (EFV, Sustiva)

Amphetamine False Positives

  • Pseudoephedrine (Sudafed)
  • Phentermine (Adipex)
  • Dimethylamylamine (DMAA)
  • labetalol
  • Bupropion (Wellbuturin)
  • Chlorpromazine
  • Metformin (Glucophage)
  • Ofloxacin
  • Promethazine
  • Trazodone
  • Fluoxetine (Prozac)
  • Methylphenidate (Ritalin)
  • Vicks Inhaler

Methamphetamine False Positives

  • levomethamphetamine
  • Metformin (Glucophage)
  • Fluoxetine (Prozac)
  • Labetalol
  • Methylphenidate (Ritalin)
  • Vicks Inhaler

Tricyclic Antidepressants (TCA) False Positives

Tricyclic Antidepressants replaced PCP on many multi drug screens because so many TCAs cause a false positive for other drugs. Having the TCA strip on your multi-panel drug test can help identify cross-reactions with other drugs.

  • Seroquel (quetiapine fumarate)
  • Trileptal (oxcarbazepine)
  • Benadryl (diphenhydramine)
  • Flexeril (cyclobenzaprine)
  • Thioridazine
  • Thorazine (chlorpromazine)

Barbiturate False Positives

  • Ibuprofen
  • Naproxen

PCP False Positives

  • Venlafaxine
  • Tramadol
  • Dextromethorphan (Robitussin, Delsym)
  • Doxylamine

LSD False Positives

  • Ambroxol
  • Ergonovine
  • Lysergol
  • Amitriptyline (Amitril)
  • Diltiazem (Cardizem)
  • Fluoxetine (Prozac)
  • Labetalol
  • Methylphenidate (Ritalin)


Additional Sources:

False-Positive Interferences of Common Urine Drug Screen Immunoassays: A Review
Alec Saitman, Hyung-Doo Park, Robert L. Fitzgerald
Journal of Analytical Toxicology, Volume 38, Issue 7, September 2014, Pages 387–396

Analysis of the cocaine metabolite in the urine of patients and physicians during clinical use
Bruns AD, Zieske LA, Jacobs AJ.
Otolaryngol Head Neck Surg. 1994; 111: 722-6

Occupational exposure to cocaine involving crime lab personnel
16. Le SD, Taylor RW, Vidal D, Lovas JJ, Ting E. .
Journal of Forensic Science. 1992; 37(4): 959-68.


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Can Drug Tests Detect Gender?

Can a Drug Test Detect Gender

We’ve all heard the stories of a man bringing his wife’s urine to cheat on a drug test and when he asks the doctor about his results the doctor responds “well you’re clean on drugs, but did you know you were pregnant?”. Can drug tests detect gender, or is this an urban legend that is an entertainment trope?

Can Drug Tests Detect Gender?

This is actually a complicated question with many aspects. In the simplest terms a drug test itself cannot detect gender. A drug test only tests for the presence of specific metabolites associated with a specific drug. There are compounds found in urine that can be linked to pregnancies and other gender specific conditions.

However urine tests are widely available that detect hCG (human chorionic gonadotropin), a hormone that is produced by the placenta of pregnant women. Many of our clients have a need for testing women for pregnancy because the type of treatment and care changes for a patient that is pregnant. It is relatively cheap to add an hCG strip to testing.

hCG Pregnancy Test
A pregnancy test detects levels of hCG in a woman’s urine. The placenta starts to release hCG as early as 14 days after fertilization.

In cases where drug tests are sent to the lab a gas chromatography and mass spectrometry instrument breaks down the sample into all its components. For confirmations a lab technician will focus on the analyte associated with the positive test strip, but all of the compounds are identified. A high level of hCG would be recognized fairly quickly.

So it is true that drug testing would identify pregnancy in cases when providers test for pregnancy or samples are sent to a lab. The assays found in drug test cups and used in laboratory immunoassay tests do not detect hCG though.

What Are the Differences in Men and Women’s Urine

In the rare case a lab technician or medical review officer suspects a subject has used a urine sample from someone of the opposite sex the sample can be put through additional analysis to support their suspicions. Even though a drug test itself cannot determine gender, other tests can indicate gender.

The biggest differences in each sex’s urine are trace hormones, but there are indicators that may cause a lab technician to become suspicious and investigate further.


  • Women’s urine can contain hCG (the analyte used to detect pregnancies).
  • Women’s urine can be contaminated by blood during menstruation.


  • Men process alcohol differently. Higher concentrations of dehydrogenaze are present after consuming alcohol.
  • Men have higher muscle mass which can increase creatinine levels.
  • Male samples can contain traces of sperm or pre ejaculate, however females can too for 8-12 hours after sex.

Foreign matter such as blood and semen are good indicators of gender, but are far from definite because men can have blood in their urine and women can have male semen in their urine after sex.

The easiest hormone to identify a person’s gender in urine is testosterone. Men produce less testosterone as they age, but will always excrete significantly more testosterone in their urine. Marijuana has been shown to suppress the production and secretion of testosterone and other androgens.  A study conducted by the Worcester Foundation for Experimental biology found that men excrete 28-250 μg of testosterone in their urine, while women excrete 2.4-8μg.

Testosterone Levels in Urine

Sex / AgeAVG Testosterone Levels
Male 18-28171 μg (range 65–250)
Male 30-3589 μg (range 45–150)
Male 42-5581 μg (range 28–159)
Female 23-376 μg (range 2.4–8)

Can Drug Blood & Hair Drug Tests Detect Gender?

It is almost impossible to adulterate or substitute hair or blood samples during a drug test because a subject has to physically present themselves to have samples taken. A technician will confirm the identity of the subject at the time of sample donation. Any anomalies that indicated a different gender would be investigated as a health issue instead of possible tampering.

However, the same hormones that are present in urine are present in a person’s blood, and DNA from human hair can be used to determine a person’s gender.

Hair samples can give an indication of gender simply by the length and treatment when examined under a microscope, but nuclear or mitochondrial DNA would be needed to determine gender with a hair sample definitely.

Considerations When Testing Different Genders

Even though the basic mechanisms of how a drug test works is the same whether you are testing a male or female, there are some differences you may want to account for. For example women process alcohol slower than men. It would be easier for a female to have some drinks at night and still have alcohol passing through their system the next morning.

Another consideration is that women have a much higher body fat percentage than men. A healthy middle aged male has a body fat percentage of 20% while a healthy female of the same age has a body fat percentage of 30%. Drugs or metabolites that bind to fatty tissues can be detected longer in an individual with a higher body fat content.

GenderBody TypeBF % Age 20-39BF % Age 40-59BF % Age 60-79

This doesn’t mean that a woman that you should alter results for females, but there are many instances when this knowledge is useful. For example after a failed drug test you can expect women to have a slightly longer detection time for drugs that have an affinity for fatty tissue. It can help with scheduling retests, confirming patient statements, and advising clients about detection times.

Will You Get Caught if You Use Urine From the Opposite Sex to Cheat a Drug Test?

Using urine from the opposite sex to pass a drug test will go unnoticed in the vast majority of drug screens because assays only detect the metabolite they are designed for. A male using a pregnant female’s urine would increase the likelihood of being caught because of the hCG content.

However, you are much more likely to be caught  substituting urine by a witness during screening, a cold temperature strip, suspicion from staff, or a number of other discrepancies that are present when you substitute someone else’s urine for a sample.

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Which Drug Test Do Most Probation Offices Use?

Drug Test at probation office

Drug testing parolees and probationers is one of the most complex and specialized instances of drug testing. The consequences are high and the subjects are very clever when it comes to tampering. Probationer officers and parolees alike often want to know which drug test probation offices use.

Which drug tests do most probation offices use?

The 12 Panel Clia Waived drug test is by far the most common test used by probation offices across the country. A 12 panel drug test covers all of the well known illegal drugs such as cocaine, marijuana, heroin and ecstasy as well as pharmaceuticals like opiate painkillers, Xanax, valium and buprenorphine.

Users are always finding new drugs that they can take that won’t show up on a drug test, but a 12 panel drug test pretty much covers the basics for probation office use.

Neurontin 800 mg
Neurontin was recently added as a scheduled narcotic after probation officers found their clients were taking Neurontin because it wasn’t on their drug test.

Across the United States however testing varies. Probation officers choose tests based on the drug use in their area. Almost all probation offices use instant drug test dip cards or cups, but some use 5 panels and some use 12 panels.

12 Panel Drug Tests - Lowest Price Online
12 Panel Drug Tests – Lowest Price Online

Drug Test City drug tests are made to the same standards with the same cutoff levels as most drug tests used nationwide. Purchase our 12 panel cups to see for sure what is on a 12 panel drug test .

For instance one probation office surveyed in North Carolina used 5 panel tests, but also had alcohol and benzodiazepine tests to use for probationers that used those drugs and to randomly check others. A probation office in Michigan used 12 panel tests but also used an ETG (alcohol) test.

Why 12 Panel Drug Tests?

The main reason probation offices would choose a 12 panel instant test is because it’s the most drugs you can test for in a single device and still have it CLIA waived. A CLIA waived test is important because it takes minimal instruction to use and officers do not need special training.

It is important for probation offices to use instant drug tests because they do a high volume of testing, it is much cheaper and it also allows officers to have immediate results. Positive test results will always be confirmed at a lab, and in most cases your probation officer will wait until those results come back to pursue any punishment.

12 Panel Drug Test Cup Strips shown
Probation offices can purchase Drug Test City 12 Panel Drug Test Cups for $2.70, which saves tens of thousands of dollars annually over a drug testing lab.

Drug Test Cups are preferred because the price difference is negligible and they’re much more sanitary than using dip cards.

During the last decade probation officers used 5 panel tests that would identify the use of most popular illicit drugs including heroin, marijuana cocaine and methamphetamine. As areas started to see more prescription drug abuse they started to expand to cover the most widely abused prescription medications.

In some regions it is fairly easy to get a prescription to cover this type of drug use, which slowed down agencies from adopting more comprehensive drug tests even more.

Forensic Use Only

Since probation officers are considered law enforcement, they are allowed to use drug tests that are designed for forensic use. many probation offices have started supplementing their 12 panel tests with fentanyl tests

Probation Drug Testing Changes on a Regional Level

One probationer that was released from his probation in 2007 said, “I was caught in Minnesota with Oxycontin and charged with felony possession. I was offered a plea bargain that would drop the felony to a misdemeanor in exchange for 1 year on probation, they said I was the first person to ever be caught with pain pills crushed up. Once I checked in at my probation office I noticed they only used a 3 panel drug test, so I continued using prescription painkillers the entire probation”.

States like West Virginia saw an early rise in prescription drug abuse and changed their drug testing programs to reflect that. From 1999 to 2004 deaths from unintentional drug poisoning increased 68% nationwide, while West Virginia experienced the Nation’s largest increase at 550%. West Virginia probation offices were purchasing panels for Oxycodone and other prescription medications as early as 2001.

As prescription drug abuse has increased across the country so has testing for those substances. In 2020 the majority of probation offices are using 12 panel drug tests that are comprehensive, but there are still offices that focus primarily on illicit drugs that have no medical use.

The Future of Probation Drug Testing

Probation officers change with the landscape. Many are already using additional panels to test for alcohol and fentanyl, and some probation offices have started random testing for Gabapentin (Neurontin) because probationers often turn to drugs that aren’t as well known to get high without risking arrest. Other popular replacement drugs are Tramadol, Kratom and designer drugs like spice, K2, Flakka or bath salts.

Most drug tests will include fentanyl after the FDA starts issuing CLIA waivers for those panels. Most 12 panel drug tests have removed PCP and replaced it with Tricyclic Antidepressants in the past few years.

It is a constant game of cat and mouse between probation officers and probationers trying to cheat the system. The only thing for certain is that probation officers will continue to change up and surprise probationers and the only surefire way to keep from getting your probation revoked is to obey the law and practice abstinence from drug use during your sentence.

If you’re a probation officer or probationer we’d love to hear about your drug testing program and which tests you use! Contact us and let us know.

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What Do Faint Lines on a Drug Test Mean?

The question we get asked most frequently is what do faint lines on a drug test mean?

It is very common to have faint lines on drug tests. Most at home drug tests explicitly state that a faint line is a negative result, but customers still assume that it means there is some level of the drug present.

Faint Lines on Drug Tests Are Negative

Faint lines are always negative. The purpose of a drug test is to determine whether there is less or more of a certain concentration of metabolite present in the urine. You should interpret all Drug tests on a pass / fail basis. Drug testing cups are not quantitative and cannot indicate the amount of a drug that is present in the sample.

 What Causes Faint Lines on a Drug Test?

Keep in mind on a 12 panel drug test you are actually performing 12 assays at once. Each test uses its own regeant and calibration. THC tests are notorious for having faint lines even for donors that have never smoked in their lives.

Faint Line drug test
THC tests are more likely to have faint lines because of components of the test itself as well as more natural substances interacting with the regeant.

Tests are designed for consistent results display, but each assay is never going to have identical line darkness. It would be more accurate to compare the darkness of strips testing the same drug than different strips on a multi-panel cup.

Variations in Urine Makeup

Urine is a complex substance that varies in makeup from person to person. The chemical makeup of urine alone can lead to test lines showing lighter or darker from one person to the next. Researchers published a database showing over 3,100 small molecule metabolites that can be found in urine. 1,500 compounds are created by the body alone and an additional 2,300 compounds come from diet, cosmetics, drugs and the environment.


Chemical makeup of human urineThis graph shows the components of human urine. Fake pee is often made of urea, but doesn’t have other components that affect shelf life.

External Variables

There are also dozens of variables that exist outside the laboratory that play into drug testing results.

  • Temperature of the room
  • Temperature of the urine
  • Humidity
  • Urine dilution
  • Age of the test
  • Amount of urine in the cup
  • Amount of time the cup has sat before reading results

Cross Reactivity

There are many substances that can lead to false positives, and in a similar vein many substances can cause a faint line on a drug test. People take more prescription medication, over the counter medication, supplements and vitamins these days. Rapid drug tests are testing for metabolites that those drugs are broken down into and not the drug itself . Our bodies naturally produce about 4 grams of alcohol every day.

Trace Levels

Finally trace levels of the metabolite can cause a minor fading of the assay line. It’s always the first instinct of someone to believe trace levels are what causes faint lines on drug tests, and in some cases that’s true. The target metabolites are far more reactive than any other substance that could be found in the urine. However a faint line is still a line and indicates a negative result.

Addressing Faint Lines on Drug Tests

Even though you will always have to deal with faint lines you can do things to make sure your results are as accurate as possible.

  • Tightly control independent variables during testing and storage, especially temperature.
  • Consistently read results at the 5 minute mark.
  • Discard expired tests.
  • If possible test first thing in the morning before the subject can ingest water.
  • Have subjects report all medications, supplements, and energy drink consumption.
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What Does CLIA Waived Mean?


Almost all point of care drug tests are advertised as CLIA waived. Customers often want to know what does CLIA waived mean, and why is it so important?

CLIA stands for Clinical Laboratory Improvement Amendments. CLIA is a set of guidelines and regulations that are jointly enforced by the CDC (Center for Disease Control), CMS (Centers for Medicare and Medicaid Services) and FDA (Food and Drug Administration).

In its most basic form the FDA categorizes all diagnostic tests according to complexity. There are 3 levels of complexity:

  • High Complexity
  • Moderate Complexity
  • Waived

CLIA Waived Drug Tests

For a test to be waived it must :

  1. Require minimal scientific and technical knowledge to perform the test and the knowledge must be easily obtained through on the job instruction with minimal training.
  2. Regeants must be pre-packaged, reliable, stable and require no special handling, precautions, or storage.
  3. Operational is automatic or easily controlled.
  4. Calibration, Quality Control & external proficiency testing materials must be readily available and stable.
  5. Test system troubleshooting is automatic or self correcting, or clearly described and requires minimal judgement.
  6. Minimal interpretation and judgement are required to analyze results.
  7. Have been issued a CLIA waiver and number by the FDA.

Basically a CLIA waived test is a test that can be performed by anyone at home or in any setting without special raining or certification. Besides the requirements for being fool proof, a test must apply and receive a CLIA waiver or be amended onto an existing CLIA waiver with updated inserts and labeling. Someone can build a drug test identical to our CLIA waived 12 Panel Test and it wouldn’t be considered CLIA waived until they were issued the waiver by the FDA.

CLIA Enforcement

For a multi-panel drug test each strip and the device must be covered under the waiver, however enforcement is carried out at the state level and many states do not strictly enforce this. Every strip on the test must be CLIA waived for the test to be CLIA waived. Most states have employees within their state health departments that are contracted directly with the CMS as CLIA surveyors.

Some states have their own licensure and infrastructure for enforcing CLIA. Their regulations are usually more stringent, but at the very least meet the federal requirements.

At the time of this publication the only two states with independent licensure are Washington and New York. Washington’s program is run by the Office of Laboratory Quality Assurance and New York’s program is called the Clinical Laboratory Evaluation Program under the State of New York Department of Health.

For a test to be CLIA waived the FDA must inspect the facility where it is manufactured. During the Coronavirus pandemic the FDA suspended drug and medical device inspections. For the majority of drug tests an existing CLIA waiver is amended for slight changes to labeling and recently waived tests are produced by facilities that are already producing CLIA waived drug tests.

False Advertising

Just because a drug test is advertised or labeled as CLIA waived does not mean it really is. The only sure way to check is to see if the test and all its component strips are listed correctly in the FDA CLIA medical device database.

According to Alicia Williams, a CLIA Surveyor for the state of Oklahoma, many drug test cups that are re-labeled do not file the appropriate paperwork with the FDA and even though they are advertised as CLIA waived they do not meet the guidelines. Suppliers often sell these tests for months and potentially thousands of labs, healthcare facilities and other businesses are using tests that they believe are CLIA waived but aren’t.

Reasons You May Need a CLIA Waiver

You will need a CLIA waiver if you plan on charging someone for testing and do not have an employee that is properly certified in conducting moderate or high complexity tests.

You will need a CLIA waiver if you charge insurance for drug testing at a medical practice.

You will need a CLIA waiver to test employees if you do not have staff properly certified in conducting moderate or high complexity tests.

Where Can I Purchase CLIA Waived Tests?

CLIA waivers are not available for all types of drugs and it can take years for a facility to get new drugs issued for existing or new waivers. In this case tests can be used “for forensic use only”. For example it currently isn’t possible to get a fentanyl test that is CLIA waived, but the drug is becoming more popular. Some professionals will order a single panel fentanyl strip in addition to a CLIA waived 12 panel cup so they can send a sample for laboratory confirmation if it fails for fentanyl, but for all other purposes their testing is covered by CLIA.

For a laboratory to perform high complexity tests the Executive Director has to be a certified pathologist or have a P.H.D. with related board certification and each technician has to have an Associates Degree minimum.

Even though a test is very simple if the distributor does not complete the required filings and their tests are not listed on the FDA’s CLIA medical device database you still need the infrastructure and certifications that a high complexity lab would need.


“Oklahoma CLIA surveyors can be contacted through email and cell phone.  We encourage laboratories or potential laboratory personnel to ask questions.  We believe in a partnership between the laboratory and the CLIA State Agency to deliver accurate laboratory test results.”

-Alicia Williams, BS, MS, MLS (ASCP)
Clinical Health Facility Surveyor
Oklahoma State Department of Health


The personnel on staff in your state are usually happy to help with any questions you have. According to Alicia Williams, a clinical health facility surveyor for the state of Oklahoma, “Oklahoma CLIA surveyors can be contacted through email and cell phone.  We encourage laboratories or potential laboratory personnel to ask questions.  We believe in a partnership between the laboratory and the CLIA State Agency to deliver accurate laboratory test results.”.

CLIA Resources

CMS Website for CLIA Services

CLIA Medical Device Database

For information on the CLIA status of any of our products please Contact Us with your questions.


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What is BUP On a Drug Test?

What Does BUP mean on a drug test

BUP on a drug test stands for Buprenorphine.

When customers purchase a 12 panel drug test they usually recognize most of the abbreviations, but may be confused by the pharmaceuticals. Buprenorphine is a medication used in addiction medicine to treat opioid dependence.

What is BUP on a Drug Test?

BUP stands for Buprenorphine. Buprenorphine (BUP) is an opioid that is most commonly used to treat chronic opioid addiction. It’s often prescribed as Suboxone, which contains naloxone to discourage misuse. Suboxone is prescribed in a tablet or strip that is meant to be taken sublingually (under the tongue).

Buprenorphine (BUP) is long acting and has a low ceiling compared to its toxic level. This means that at a certain dose taking more won’t make you higher, it just wastes more of your medication. The ceiling is far below the level where the drug becomes lethal due to respiratory depression. On the contrary, Heroin has a high ceiling (the more you take the higher you get) and the level where someone is very high is close to the level where it is lethal.

Buprenorphine tablets
An 8mg Suboxone tablet contains Buprenorphine & Naloxone and is dissolved under the tongue.

Since the danger is lower and the effects last so long the government has allowed Suboxone clinics to have more relaxed guidelines than Methadone clinics. It’s also subsidized by healthcare. All of these factors has lead to buprenorphine (BUP) becoming the opioid of choice for drug users that are addicted to opiates and don’t have much money to keep up a heroin addiction. Users can get their own prescription for Suboxone or trade for it cheaply on the streets.

12 Panel Drug Tests - Lowest Price Online
12 Panel Drug Tests – Lowest Price Online

Drug Test City drug tests are made to the same standards with the same cutoff levels as most drug tests used nationwide. Purchase our 12 panel cups to see for sure what is on a 12 panel drug test .

In many areas hardest hit by the opioid epidemic users have moved to using cheaper methamphetamine to get high and buprenorphine to fight withdrawals from the oxycodone and heroin they were previously addicted to.

Pregnant mothers are given Subutex, Buprenorphine without naloxone, because it is thought to be less harmful to unborn babies.

Buprenorphine (BUP) was patented in 1965 but wasn’t approved for medical use until the early 1980s.

Buprenorphine (BUP) is a schedule III drug in the United States.

Side Effects of Buprenorphine

  • Respiratory Depression
  • back pain
  • Bladder pain
  • bloating of extremities
  • bloody or cloudy urine
  • blurred vision
  • cough
  • diarrhea
  • painful urination
  • difficulty breathing
  • dizziness
  • fever
  • headache
  • lethargy
  • loss of appetite
  • nausea
  • nervousness
  • pale skin
  • pounding in the ears
  • slow or fast heartbeat
  • stomach pain
  • tightness in the chest
  • tingling of the hands or feet
  • troubled breathing with exertion
  • tunnel vision
  • weight gain
  • weight loss

Additional Precautions

Suboxone is often prescribed in the form of a strip that could be mistaken for something else. As a sublingual medication it can be absorbed easily through the mucous membranes.

The naloxone and Buprenorphine can be very dangerous to someone that hasn’t taken Buprenorphine recently but has taken other opioids. Buprenorphine has a much higher affinity for opioid receptors and can cause immediate withdrawal like effects to the user.

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Can Fake Pee be Detected in a Drug Test 2023

Can fake pee be detected in a drug test

One of the most recent trends in tampering and adulteration of drug testing is people using fake pee as a substitute for their own urine sample. Subjects have been using other people’s clean urine for decades, but have sometimes been surprised when the urine they brought failed for more drugs than their own urine would have. People ask us “can fake pee be detected in a drug test?” because it would be a more convenient method of defrauding tests for them.

Using fake pee is more convenient and more trustworthy for someone trying to tamper with their drug test. It’s developed to match the composition and appearance of real urine as closely as possible.

12 Panel Drug Tests - Lowest Price Online
12 Panel Drug Tests – Lowest Price Online

Drug Test City drug tests are made to the same standards with the same cutoff levels as most drug tests used nationwide. Purchase our 12 panel cups to see for sure what is on a 12 panel drug test .

Can Fake Pee Be Detected in a drug test?

Fake pee is easily detected in a drug test when a laboratory is looking for it. Since more people are using fake pee to tamper with their drug test labs have started testing for analytes that are found in human urine but aren’t found in fake pee. Uric acid for example isn’t a common ingredient in much of the fake urine available.

Chemical makeup of human urine
This graph shows the chemical makeup of human urine. Fake pee is often made of urea, but doesn’t have other components that affect shelf life.

Have you ever forgot to flush after urinating and came back later to an awful smell coming from the toilet? Uric acid and certain bacteria present in urine are left out of fake pee so it has a longer shelf life. Fake pee wasn’t designed to completely fool lab equipment, so it will likely always be detected when your sample is sent to a lab for confirmation. Besides uric acid there are approximately 12 other analytes that are expelled in human urine that would not be stable in a product that needs to be stored more than a few days.

Other components of human urine
This graph represents the 0.2% of components that are categorized as “other” in the first graph. All of these substances are expected to be found in your urine sample.

We suggest that companies and medical practices perform visual confirmations on their drug tests. This means an employee will confirm that the sample originated from the donor as a witness.

It would be very challenging for someone to substitute fake pee for their own urine with a proper visual confirmation. Prosthetics are made to help trick employees, but they have been known to malfunction and are easily noticed by most witnesses.

There are also belts available that have a reservoir and tubing to help trick a witness. The belt uses body heat to keep the temperature of the urine warm enough to activate a temperature strip. Again, these devices are fairly easy to identify especially if the witness has been trained to catch people smuggling clean urine.

Fake Pee Belt
The fake pee belt is easy to conceal, but would be easily spotted during a visual screening.


Can fake pee be detected in a drug test? It can easily be detected in a drug test, and a witness can negate people’s ability to defraud simpler tests.

Does Fake Pee Ever Work?

Fake pee was originally developed as a control tool for scientists and lab technicians to use for testing. It helped eliminate variables such as dilution, composition, and contamination during experiments that required human urine. It could be stored for longer periods without refrigeration.

During a point of care drug test the fake urine will test like clean urine. Since a qualitative drug test is only confirming whether a certain drug’s metabolites are present above a specified level in a substance diluted to the level of average human urine, water will even work if there are no metabolites present. This is why most organizations perform a visual confirmation, use cups with adulterant test strips, or randomly lab negative samples.

If you are trying to cheat on a drug test the likelihood of being caught is directly related to the policies of the organization testing you. The more time and money they invest on stopping adulteration the harder it will be for you to tamper with a test.

As far as a home test cup goes there are basically 2 categories. Cups with adulteration strips and cups without adulteration strips. Most fake urine available will pass on both cups because they are engineered to have perfect readings on most adulterant tests. Urine adulteration checks include:

  • Creatinine
  • pH
  • Nitrite
  • Specific gravity
  • Glutaraldehyde
  • Bleach
  • Oxidant/pyridium chlorochromate
urine adulterant strip guide
This key shows the results of common urine adulteration strips. Some strips test the properties of urine and some check for the presence of adulterants.

However, all it takes is for the person who is giving you the drug test to watch you pee and you won’t get a chance to substitute your fake pee for your sample.

Both types of cups usually have a temperature strip however, and a sample that doesn’t register will likely trigger suspicions.

If the witness isn’t paying attention and you have taken measures to keep your fake pee warm enough to register at body temperature then you might get away with it. The real question is, are you willing to get caught?

Risks and Consequences of Using Fake Pee

The investment in combating adulteration is often directly correlated to the consequences of catching someone tampering with their drug test. A person on probation will face a zero tolerance policy and tampering with a urine sample will result in immediate jail time. A patient that is prescribed narcotics may not be watched as closely but will be expected to produce a sample that is positive for the drugs they are prescribed. Most doctors will refuse to prescribe and note it on their chart if a patient is ever caught tampering with a drug test.

Employment tests vary, but most of the time they either outsource their testing to a company that has strict guidelines for identifying adulteration, or they run their own program and put a lot of effort into making sure it’s not wasteful. An exception would be a company with relaxed guidelines that only drug tests to satisfy an insurance guideline.

In any case, it would put a company in a position of liability if they hired a potential employee that tampered with their drug test. In almost every case you will not be hired, and in some cases you could be blackballed by an entire industry for tampering with a drug test. Tampering with a drug test is in many ways worse than failing one.

Boeing fired CNC Machinist Michael Kelly after catching him trying to substitute a liquid for his own sample during a drug test. Kelly sued Boeing for wrongful termination, but lost the suit and could not have won even it was proved he did not tamper with the drug test because Boeing acted in good faith.

The consequences of attempting to defraud a drug test are becoming more serious. Several states have passed laws that make it illegal to use, possess, sale, manufacture or distribute fake pee. In many of those states there are sections that stipulates that if a technician catches someone using fake pee or attempting to defraud a drug test they must report it to the authorities or risk being penalized themselves.

Synthetic Urine Bans by State

In the United States there is currently no federal law banning the sale or use of fake pee, but 19 states have enacted legislation regarding synthetic urine.

  • Alabama’s SB111 prohibits the manufacture, marketing, sale, distribution, use, and possession of synthetic urine or a urine additive. 1st offense is a class B misdemeanor.
  • Oklahoma Code §63-7002 is a comprehensive bill covering fake urine and popular adulterants. The penalty is a misdemeanor.
  • Arkansas Code § 5-60-201 is a comprehensive bill covering fake urine and popular adulterants. The penalty is a class B misdemeanor.
  • South Carolina Code 16-13-470 is a comprehensive bill covering fake urine and popular adulterants. First offense is a misdemeanor, second offense is a felony.
  • Mississippi H.B. 1080 the popular “Urine Trouble Act” is a comprehensive bill covering fake urine and popular adulterants. The penalty is a misdemeanor with a 6 month jail sentence and $1,000 fine.
  • Tennessee § 39-17-437 makes it illegal to use, possess or sale synthetic urine. Use or possession is a class A misdemeanor, sales is a class C misdemeanor.
  • Florida Statute 817.565(b) doesn’t mention fake urine specifically, but makes it illegal to sale, use, distribute, manufacture or advertise substances intended to defraud a drug test.
  • Missouri Representative Nate Tate has been presenting bills to revise Chapter 579 to include bans on synthetic urine.
  • Utah HB 0016 76-10-2203 makes it a criminal offense to distribute, possess or sell synthetic urine.
  • New Hampshire 2016 SB 361 bans the sale and possession of synthetic urine and urine additives.
  • West Virginia §60A-4-412 makes it illegal to sell, give away, distribute or market synthetic urine. It also makes it illegal to knowingly try and defraud a drug test.
  • Indiana’s Adulterant and Synthetic Urine Ban makes distributing synthetic urine with the intent of assisting a person in defrauding a drug screen a misdemeanor.
  • North Carolina General Statutes § 14-401.20 is a law covering many aspects of fake urine and drug test cheating with the penalty of a class I felony for a 2nd offense.
  • Wisconsin 2015 AB658 criminalizes the use, possession, manufacture, distribution and advertisement any substance or device meant to defraud, circumvent, interfere with or provide a substitute for a bodily fluid sample.
  • Wyoming § 6-3-614 is a comprehensive bill covering fake urine and popular adulterants. First offense is a misdemeanor, second offense is a misdemeanor.
  • Kansas
  • Michigan Article 23 employees are barred from interfering with any test procedure or tampering with any test sample
  • Arizona
  • Georgia

In conclusion, can fake pee be detected in a drug test? Yes it can, and you’re even more likely to be caught by a witness or technician. It can be detected and penalties are getting stiffer for people that get caught.