When police said they'd found drugs, you laughed it off. You knew you didn't have any illegal drugs in the house.
Then they got out a test kit, and the chemicals changed colors. They arrested you, saying that the test had shown you did have illegal drugs. Now you're facing serious charges and you can't believe it.
One important thing to note is that those tests aren't all that trustworthy. Many common items that you could have around the house will trigger them.
For example, one study tested Hershey's chocolate, and it claimed to have found marijuana. That study also tested Tylenol PM, a medication you can buy over the counter in seconds, and the test said it had found cocaine.
Another common example is soap, which has been shown to trigger a GHB test. If you've ever used Mucinex, watch out, as tests can claim that it is actually morphine or heroin.
As you can see, this is a serious issue. Police are often trying to work quickly, in conditions that aren't optimal. Officers may not be well trained to use the tests. They may already be assuming you'll have drugs before the tests are done. Many things can influence the way the situation plays out. Then, when a simple household item triggers the test, you're on the way to jail for something you never did.
In a case like this, it's critical for you to know all about your legal rights. Be sure you understand exactly what defense options you have and never assume that a positive test means there's nothing you can do.
Source: The Expert Institute, "Field Drug Testing: How to Confront False Positives with Expert Testing," Anjelica Cappellino, accessed Sep. 28, 2017