If you or a loved one has had a positive drug test, the most likely occurrence is that it’s actually positive. False positives are extremely rare on many drug tests. But, in some very rare occasions, tests can show up as false positives. Here, someone is flagged as having a substance in their blood indicating drug use – normally from a substance that breaks down in similar ways or which creates the same substances. In addition, other flukes, such as mislabeling samples can result in false positives on a drug test.
While there are many ways false positives can occur on drug tests, there is a single way out of all of them. You can ask for a hair or nail test – which will conclusively show drug use – sometimes as long as a year ago. Because most employers will give you a retest, will request a more in-depth test, or will be willing to discuss with you – that’s the logical next step. In addition, some states actually offer laws allowing employees to request a re-assessment of a positive drug test.
However, if the drug test is for a loved one, it is critical that you approach them first. Chances are, a positive is a positive, and they are actually using. There are exceptions, but false positives are very rare.
Most workplace drug tests use urine or saliva tests to assess whether someone has been using. These tests are, on average, accurate for 3-5 days after the last drug use –depending on the drug in question. Saliva and urine tests are the fastest, cheapest tests which can be run and are extremely accurate. In fact, every positive test has been run twice– with the same result.
In most cases, a lab analyst goes into the workplace and collects samples. Here, a cheek swab is the most likely. Samples are taken, inserted into a plastic tube, and labelled. Then, they’re sent to a lab for testing. Each tube is entered into the machine and then entered into an immunoassay test. The biological sample is split into two, for an initial test and a confirmation test. If the first immunoassay test comes up positive, the lab runs a second type of test to verify results.
The second test, Gas Chromatography Mass Spectrometry (GC-MS), plays a crucial role. Unlike the initial immunoassay screening, which can sometimes yield “false positive” results, GC-MS offers a higher level of accuracy. This advanced technique provides a “chemical fingerprint” unique to each substance, ensuring precise identification.
Confirmatory testing, whether using GC-MS or Liquid Chromatography Mass Spectrometry (LC-MS), is essential for delivering reliable results, especially in high-stakes situations like emergency medicine. These tests are meticulously validated to avoid the inaccuracies associated with initial screenings.
In addition, if your result is not screened using a GC-MS test, your employer is legally required to grant it to you. If both tests are positive, the lab reports a positive drug test. This two-step approach ensures that the results are both accurate and legally defensible.
So, what can go wrong here? In most cases, there are just two scenarios in which something could go wrong.
Human Error – If the lab improperly labelled samples, you might be receiving someone else’s result. This is especially likely if there is more than one person in your workplace with the same or a similar name. It’s also slightly possible the lab inserted the wrong results into your screening. However, this is unlikely. The chance that it can happen means that some states protect your right to request a retest.
Contaminates – In some cases, you get a false positive because you’ve taken medication or consumed food that creates molecules and enzymes similar to those created by drugs. For example, nearly everyone is familiar with the poppy seed creating a false-positive for opiate use. Unfortunately, there are many things that can trigger a false positive. For example:
This list is non-comprehensive. However, it should give you a good idea of what types of over the counter and prescription medication might trigger false positives. For this reason, many employers and labs encourage people getting a drug test to bring along a list of any medication they might be taking. This will be taken into account during the test to further reduce the chances of a false positives.
However, most labs are already very aware of which medications result in false positives. There are standard procedures in place to identify and screen out any known false positives. Therefore, it’s highly unlikely that you can consume a few bagels with poppy seeds and trigger a false positive. For example, labs now look at the cycle count and volume of the enzyme in the blood – which can’t be triggered by poppy seeds in the same volume until you eat several pounds of them. So, false positives because of contaminates are also relatively rare.
False positives comprise some 1.75% of all blood tests, but up to 90% of false positives are simply showing the wrong drug. For example, MDMA usage frequently creates a false positive for amphetamine usage. The person triggers a false positive for amphetamine usage but was using MDMA. The further 10-50% of blood tests not attributed to drug confusions are almost entirely linked to human error. This means that you can easily request a retest.
However, most employers will choose to retest using a hair or nail sample rather than saliva or urine. This is because hair and nails show a longer history of drug use, and you can’t fake it by simply not taking drugs for a few days.
Modern drug tests almost never result in false positives. GC-MS testing, including dual testing, often means that the chance of a false positive is close to 0%. If you do come up with a positive test result, it’s important to discuss it, ask your employer for a retest, and, if they are not cooperative, to pursue the issue with an employment lawyer. If you don’t use and you have a false positive, a hair or nail drug test will clear your name.
However, if the test is for a loved one, make sure you have an open discussion with them before taking steps. A hair or drug test showing a longer history of drug use could further incriminate them and make it more difficult for them to keep their job. If your loved one is using, their best next step would be to ask for help getting into rehab or treatment or to do so on their own. Many employers offer assistance programs, insurance providers are required to offer assistance on rehab, and you can take up to 90 days of unpaid leave from work to attend that rehab. However, if you do have a positive drug test, it may be too late to keep your job. That depends on your employer, the situations in which drugs were being used, and their policy.
Good luck with your false positive drug test.
If you have any questions about our drug rehab and alcohol rehab programs, contact us today to speak in complete confidence with one of our experienced and caring addiction treatment team.
When it comes to confirmatory testing using mass spectrometry, the presence of amphetamine or methamphetamine in a person’s system can lead to interesting insights.
These distinctions highlight the importance of knowing the specific substances consumed and their metabolic pathways to interpret test outcomes accurately.
In confirmatory tests, certain drugs are classified as true positives for methamphetamine due to their chemical makeup or metabolism. These substances either contain methamphetamine or transform into it within the body. Here’s a breakdown:
Understanding these substances and their relation to methamphetamine can provide crucial insights into drug testing results. Each plays a role in how methamphetamine is detected and confirmed.
When it comes to confirmatory tests for amphetamines, certain drugs are recognized as true positives. These include substances that either contain amphetamine directly or metabolize into it.
Common Amphetamine-Containing Drugs:
Additional Compounds that Metabolize to Amphetamine:
Less Common but Noteworthy Drugs:
These drugs, whether through direct content or metabolic transformation, will typically yield a positive result for amphetamine in detailed drug screenings.
Each tube is entered into the machine and then entered into an immunoassay test. The biological sample is split into two, for an initial test and a confirmation test. If the first immunoassay test comes up positive, the lab runs a second type of test to verify results. The second test, a Gas Chromatography Mass Spectrometry (GC-MS), is a more thorough test, and is more likely to have a false negative than the initial test.
Conducting a second confirmatory test in forensic toxicology is crucial due to the potential for “false positive” results in initial screening tests. These initial tests, while effective for quick assessments, can sometimes yield misleading outcomes. This is why samples are sent to laboratories for a more rigorous confirmation process.
The laboratory employs advanced techniques like gas chromatography (GC) or liquid chromatography (LC), each coupled with mass spectrometry (MS). These methods are designed to minimize the risk of false positives associated with immunoassay screening techniques.
The confirmatory test provides a “chemical fingerprint” unique to each drug. This specificity ensures that the results are both reliable and accurate, a necessity in forensic toxicology where precision is paramount. By employing such advanced methodologies, confirmatory tests bolster the integrity of toxicological evaluations, providing definitive evidence that can withstand scrutiny in legal contexts.
Mass spectrometric analysis is vital because it offers a detailed chemical profile of substances, distinguishing between compounds with high precision and significantly reducing the risk of false identification.
Screening tests are limited by their susceptibility to false positives, which can lead to incorrect conclusions if not verified by more accurate confirmatory methods.
The reliability of confirmatory tests stems from their ability to produce a unique “chemical fingerprint” for each drug, which reduces the chances of false results and provides a definitive identification.
Confirmatory testing employs advanced techniques such as gas chromatography (GC) and liquid chromatography (LC), both of which are paired with mass spectrometry (MS) to ensure precise analysis.
In addition to MDMA, several other substances can also cause false positives in amphetamine immunoassay tests. These include:
These examples illustrate how both prescription and over-the-counter medications can impact the accuracy of amphetamine screening tests. Being aware of these possibilities is crucial for accurate diagnosis and treatment planning.
Medications from various drug classes, including decongestants (pseudoephedrine), antidepressants (bupropion), and beta-blockers (labetalol), have been known to trigger false positives for amphetamines.
Prescription medications such as phentermine (Adipex) and bupropion (Wellbutrin) can indeed cause false positives in amphetamine screenings.
Yes, over-the-counter medications like those containing pseudoephedrine, such as Mucinex-D and Sudafed, can result in a positive reading for amphetamines.
A variety of drugs can lead to false positives in amphetamine tests, including amantadine, bupropion, chlorpromazine, desipramine, ephedrine, labetalol, mexiletine, phentermine, pseudoephedrine, and trazodone.
False positives are extremely rare on many drug tests. But, in some very rare occasions, tests can show up as false positives. Here, someone is flagged as having a substance in their blood indicating drug use – normally from a substance that breaks down in similar ways or which creates the same substances. In addition, other flukes, such as mislabeling samples, can result in false positives on a drug test.
Immunoassays, a common method used in drug tests, are based on the principle that antibodies can recognize and bind to specific drugs of interest. However, while these antibodies are designed to be highly selective, they are not flawless. They are unable to bind exclusively to a single drug, which introduces a small margin for error.
The intricate nature of drug metabolism and the complexity of chemical interactions in the body further complicate the situation. While immunoassays are powerful tools, understanding their limitations helps us comprehend why false positives, though rare, can still occur.
In most cases, a lab analyst goes into the workplace and collects samples. Here, a cheek swab is the most likely. Samples are taken, inserted into a plastic tube, and labelled. Then, they’re sent to a lab for testing. Each tube is entered into the machine and then entered into an immunoassay test.
Understanding Immunoassays
Immunoassays operate on the principle that antibodies are capable of recognizing and binding specifically to the drug of interest. These antibodies are crafted to be highly selective, meaning they are designed to bind preferentially to the target drug. However, this does not eliminate the possibility of them attaching to other substances with similar chemical structures, leading to what’s known as a “false positive.”
It’s important to note that creating an antibody that binds exclusively to a single drug is currently beyond our capabilities. Given the vast array of drugs and their metabolites, evaluating all potential false positives is not feasible. This complexity underscores the need for additional testing to confirm results.
The Testing Process
The biological sample is split into two parts for an initial test and a confirmation test. If the first immunoassay test comes up positive, the lab runs a second type of test to verify results. The second test, a Gas Chromatography Mass Spectrometry (GC-MS), is a more thorough test and is more likely to have a false negative than the initial test. In addition, if your result is not screened using a GC-MS test, your employer is legally required to grant it to you. If both tests are positive, the lab reports a positive drug test.
By understanding both the principles behind immunoassays and the testing process, you gain a comprehensive view of how drug screening is conducted and verified.
Evaluating every possible false positive is impractical because of the sheer number of drugs and their metabolites, making comprehensive testing infeasible.
It’s challenging to create antibodies that only bind to one drug due to the complex nature of chemical interactions and similarities among different compounds.
False positives can happen when antibodies bind to other substances that share similar chemical traits with the target drug, leading to erroneous results.
The selectivity of immunoassays comes from antibodies that are crafted to bind preferentially to particular drugs, focusing on unique chemical structures.
Immunoassays use specially designed antibodies that latch onto specific drugs, allowing them to detect the presence of these substances in a sample.
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