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Are roadside drug tests always accurate?

On Behalf of | Aug 12, 2021 | Criminal Defense

No. There is substantial evidence that the preliminary drug tests police officers use during traffic stops are not always accurate. As a matter of fact, the tests are known for false positives.

In 2016, the nonprofit newsroom ProPublica published a series of investigative reports on these drug tests. First, they discovered that the cheap roadside tests – which typically cost about $2 – are generally inadmissible in court. Instead, the substance must be sent to a certified lab to be tested by a chemical analyst.

What the roadside tests are generally used for is to develop probable cause to charge people. In other words, the police use these field tests for their preliminary result. If that preliminary result is positive for drugs, it’s usually enough to justify an arrest – but not a conviction.

Still, it’s troubling that an inaccurate test would be used at all, and it appears that these tests are often inaccurate, according to ProPublica. When people are charged with a crime based on a faulty drug test, they may feel they have no choice but to plead guilty even though they’re not.

How do the tests work?

The tests are convenient to use. The officer obtains a test sample, often by searching the car during a traffic stop. They drop the test sample into a pouch of chemicals and wait for a chemical reaction to take place. The chemical reaction is indicated by a change in color. The officers are instructed that different colors indicate a positive result for various illegal drugs.

Unfortunately, ProPublica found that many legal substances can sometimes create the same colors as illegal substances. For example, in one case uncovered by ProPublica, an officer found a suspicious white substance on the floor of a car. A roadside drug test came out positive for crack cocaine. When the same sample was taken to an accredited lab, it was determined to be a combination of aspirin and caffeine. Perfectly legal, but the young man involved ended up pleading guilty before the final test was obtained.

The tests routinely lead to false guilty pleas. By one count, 74% of those convicted of drug crimes had no illegal drugs at the time of their arrests. Many of those affected continue to serve time or face long-term consequences from pleading guilty.

The largest manufacturer of drug field tests told ProPublica in 2016 that “field tests are specifically not intended to be used as a factor in the decision to prosecute or convict a suspect.”

Since that ProPublica report, prosecutors around the country have begun vacating convictions that were obtained after disputed drug field tests. In other cases, defense lawyers began challenging prosecutors based on these sometimes faulty tests.

What should I do if I dispute a drug field test?

The most important thing you can do is talk to an experienced criminal defense attorney. Your lawyer will want to know the basis for your dispute and any evidence you have to back up your story. Then, he or she can challenge the results of the test that was used to arrest and charge you.

You need someone compassionate who will believe you. You need a lawyer who will go the extra mile to help.