How Accurate Are Drug Tests?
How accurate are drug tests? It depends on a lot of factors, including the type of test and how it’s administered. Here’s what you need to know.
When you take a drug test, how much can you trust the results? What are the chances that a drug you took a week or two back will simply not show up? And on the other hand, what are the chances that something completely innocent and legal that you ingested recently will cause you to test positive? target="_blank">How accurate are drug tests? Well, it depends on a lot of factors, including the type of test and how it’s administered. Here’s what you need to know.
The most common type of drug test for employers is urine testing. However, even that has two different types. Immunoassay urine testing is the simplest, and can be done on site. It’s also less accurate. There are a variety of things you can do to trigger a false negative on an immunoassay test, such as drinking a lot of water and/or cranberry just before the test. This dilutes the sample, so the drugs don’t show up.
However, while drinking a lot of fluids may cause the test to read negative, it also raises a number of red flags. There will be fewer electrolytes in the urine than typically show up, and the color will be clear instead of yellow. When these factors are detected, a second test must be performed, this time the much more accurate gas chromatography/mass spectrometry, or lab test. A more thorough analysis makes false negatives much less likely.
Other types of drug tests can have false negatives as well—even blood tests, which are widely considered to be the most accurate. While some drug tests take an entire vial of blood, others take just a drop, from a pinprick. In a sample that small, low levels of illicit substances are often undetectable.
What can cause a drug test to read positive, even if you haven’t taken any drugs? There are a number of things that can do it, including over the counter medications and even foods. Eating poppy seeds, for instance, can cause you to test positive for morphine and opiates, since those drugs are made from the poppy plant. (Though for the record, you’ll only test positive if you eat a large quantity of them.)
Likewise, if you take cold and allergy medicine, or nasal spray, you may test positive for amphetamines. And if you take Advil or Ibuprofen, you may test positive for everything from marijuana to barbiturates to benzodiazepines.
And that’s just readily available substances. If you’re legally taking prescription drugs, many of them contain substances such as steroids, amphetamines, and benzodiazepines, in carefully controlled doses to treat specific issues. But you’ll still test positive for them in a drug test.
What about CBD, though? CBD is now legal at the federal level, as well as in most states, and so has become much more commonly used. CBD products can even be purchased in many drugstores and grocery stores across the country. Will this legal, over the counter product derived from the same source as marijuana, cause you to test positive? It’s highly unlikely. Marijuana tests specifically look for THC. While many CBD products do contain THC in trace amounts, it’s typically not enough for a positive test result.
If you do worry that you’re going to get a false positive from something perfectly innocent, the best thing to do is to talk to your doctor about it, as well as to the test administrators, and see what arrangements can be made.
No drug test is 100% accurate. Even lab tests can be subject to human error. That’s why it’s so important to know what different kinds of drug tests are like and what they’re searching for. With a bit of knowledge and preparation, you can be sure to test negative and be declared clean and drug free.
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