You may have heard that poppy seeds in your salad dressing or bagels can mess up a drug test and cause you to test positive for opiates in your body. yeah. Although there are some caveats to this (cleaning and proper treatment of the seeds can remove contaminants, and cooking tends to remove the dirt) significantly reduced It is true that poppy seeds can be a problem. Although poppy seeds themselves do not actually contain opiate compounds, they often contain Contains flower sap containing opiates Processing.
But poppy seeds aren’t the only thing that can skew rapid drug tests. “There are a wide variety of things that can cause a false-positive result,” he says. Gwen McMillina toxicologist and professor of clinical pathology at the University of Utah. Poppy seeds are not actually the cause error McMillin points out that it’s a positive. “[Contaminated] “Poppy seeds actually contain opiates,” she says, but many drugs, even common over-the-counter medications, can confuse tests for completely different compounds.
most Commonly used types Rapid drug tests are called immunoassays. These tests vary widely and are created by many companies. Their various versions can screen for amphetamines, benzodiazepines, PCP, opiates, synthetic opioids, marijuana, and other controlled substances. Antibodies built into the test react with compounds selected to indicate possible drug use, metabolites that the body excretes in the urine. However, this test is not looking for a precise target substance that can be used for screening. McMillin compares them to a wooden game board with slots for marbles. Marbles of the same size and shape fit into the same hole.
Another analogy, she says, is a fishing net. “Nets are designed to catch fish, but we don’t know exactly what kind of fish we’re catching,” she says. Popular science. “Immunoassays are really great in that they can catch all kinds of things that look like fish. That’s really important if you’re just trying to do a screening…but then you get false positives. I will.”
Antibodies are the most important part of immunoassay design, and aiming for specificity while ensuring that all relevant classes of controlled substances are included in the first line of detection can be a difficult balancing act. . False positives are often the result of range selection by the test creator. But they also arise due to fundamental chemical constraints. Certain drug groups, particularly amphetamines, are metabolized into small, nondescript molecules that resemble many things, Algren says.
These include cold medicines, antihistamines and decongestants, antidepressants, blood pressure medications, diabetes medications, and more. long list of things It can lead to false-positive screening for amphetamines. Over-the-counter cold medicines can also manifest as PCP. Codeine, some antibiotics commonly used to treat urinary tract infections, high blood pressure medications, and anti-nausea medications are Some examples of tablets that False positives may occur For opioids and opiates. Quinine, an antimalarial compound used as a flavoring agent in tonic water, can also trigger some of these tests. CBD products and even certain types of CBD products. baby wash Can show up as a positive result on a test for cannabis/THC. And researchers are discovering A previously unknown example Always detect cross-reactive compounds.
Sensitivity is also an important consideration. Manufacturers don’t want tests to miss any drugs that are present, but rapid tests can detect false, accidental, or even secondary exposures if tests are designed with low enough thresholds. There is a gender.
These weaknesses are widely understood among toxicologists, and although immunoassay tests come with package inserts listing potential cross-reactivity with non-targeted drugs, patients are not advised of these in hospitals and delivery wards. Clinicians performing tests may not be aware of all of these weaknesses. Many legal and common routes Positive urine drug screen. And when time is limited and confirmatory testing is not ordered, problems can arise. Multiple lawsuits have been filed against hospitals in recent years. The newborn was placed in a foster care facility. Based on parents’ rapid drug test results. Patient care could also be compromised if rapid drug screens were used as the sole basis for approving surgeries and other treatments, McMillin said.
False negatives are not uncommon. Some tests are not sensitive enough to detect the concentration of drugs circulating in a person’s body. Also, some new substances may not actually be detected in tests that are theoretically intended to reveal their existence. For example, synthetic and semi-synthetic opioids such as fentanyl and oxycodone are not detected by all opiate drug tests because they have different metabolites and constituent chemicals. This, too, can cause problems for patients and can even lead to people being unfairly excluded from chronic pain management programs, with false negative tests allowing health care providers to ensure that patients are not following prescriptions. He said it could lead people to mistakenly believe they are not taking their medication. Adam Algrena pharmacotoxicologist and emergency physician at University Health Hospitals and the University of Missouri-Kansas City.
Algren and McMillin said that in an ideal situation, a surprising result from an immunoassay drug test would be confirmed by a more specific and accurate follow-up test. However, these time-consuming and expensive confirmatory tests are not used in all hospital systems or practices. “I think many physicians take the immunoassay results right away as the final result and make decisions based on that without looking at it or considering whether there are other implications,” Algren says. says.
“Personally, I don’t feel that confirmatory testing is getting enough attention,” McMillin agrees. Both experts say they want that to change.
This story is part of Popular Science’s Ask Me Anything series, in which we answer the most outlandish and mind-blowing questions, from the mundane to the wild. Is there something you’ve always wanted to know? Please contact us.
