How Do Cops Test Drugs?

How do cops test drugs?

Imagine you are pulled over for speeding and, as you are talking to the police officer, he says “what’s that,” as he points to a crumb of soap on your floorboard. The officer asks you to step out of the car, mumbling something about backup into his radio as you open the door…

You are still trying to explain to the officer that, although it may sound odd, people really do cut up bars of soap and use them to fish for catfish – those suckers will eat anything – when the officer says “Aha!”, waving a blue test tube in the air.

Could this really happen? How do cops test drugs anyway – are those tests reliable? How long will it take for the lab results to prove you are innocent? Will they prove you are innocent? What if you can’t afford bond to get out of jail while you wait for the test results?

How do Cops Test Drugs on the Roadside and for Court?

There are two basic types of drug tests used by law enforcement – “field tests” used on the roadside or on the fly before making an arrest, and the more comprehensive tests that are used in crime labs.

Field Tests

Since the 70s, police have used simple roadside drug tests, that often cost no more than a few dollars apiece, to determine whether a substance they find is an illegal drug:


Except these cheap, color-coded drug tests are not reliable. They never have been, and crime labs have long since moved to testing with mass spectrometry:


Field tests are never admissible at trial, however, because they are unreliable and prone to errors:


Laboratory Testing

When a drug case is called for trial, the prosecutor must present evidence that the alleged drugs were tested by a competent lab using competent techniques – often, mass spectrometry.

But how long does it take for drug results to come back from a crime lab? In my experience, it could take anywhere from a few months to never… What happens to a drug defendant in the meantime?

Although everyone knows the tests are not reliable, judges and prosecutors will assume that the results are valid. A defendant who cannot afford bond will stay in jail. Prosecutors will offer plea bargains – sometimes offering a more lenient sentence if the person pleads guilty before they get the drug test results from the lab, and innocent people will take the deal so they can go home or receive a lighter sentence.

What Happens When They Get It Wrong?


There are plenty of examples, just in media reports, of people who have been arrested, charged, and even convicted of drug crimes based on faulty roadside tests.

Shae Werts: Georgia Southern Quarterback Arrested for Bird Poop

For example, Georgia Southern quarterback Shai Werts was pulled over for speeding. When police saw bird poop on the hood of his car, they insisted that it must be cocaine:

Werts was pulled over on Jul. 31 and charged with speeding and cocaine possession. Despite the extreme implausibility of powder cocaine just sitting comfortably on the hood of a car going 80 mph, police and media outlets acted like it was Werts who had the ridiculous story, not the cops who confused bird poop and cocaine.

But, didn’t the police test the substance to confirm it was cocaine? According to the officer, they did – the bird poop turned pink, and therefore it was cocaine…

Browder [the officer]: “What’s that white stuff on your hood, man?”

Werts: “Bird s–t.”

“That ain’t bird s–t.”

“I promise you, that’s bird doo doo.”

“I promise you, it’s not though.”

“I swear to God, that’s bird doo doo.”


This case got national media attention because it was a football player, but how often does this happen?

Innocent People Go to Jail Because of Faulty Field Tests

It’s impossible to say exactly how many people are charged with drug crimes based on faulty roadside tests. Many plead guilty before the lab results come back, many more are dismissed by the prosecutors without revealing the reason for the dismissal, and incident reports typically do not reflect false positive drug test results.

Even so, reporters in Georgia found over a hundred examples of false positive drug tests by looking through police records, including cases where the defendant pled guilty:

Based on their analysis of Georgia police records, the reporters found that at least 145 people were wrongly charged with felonies after “a field test falsely claimed they had drugs. Instead of ecstasy, cocaine, or methamphetamines, people jailed actually had common items like incense, headache powder or cleaning supplies.” At least three people were found to have pled guilty “before the lab results came back.”

Pro-Publica report found that false-positive roadside test results are common, and that “a minimum of 100,000 people nationwide plead guilty to drug charges that rely on field-test results as evidence.”

Other high-profile cases have gotten media attention. A woman in Georgia spent three months in jail after police arrested her for possession of cotton candy… the “suspicious blue substance” tested positive for meth, she was arrested and charged with trafficking in meth, and a judge set her bond at $1 million (a higher bond than many murder defendants).

Another woman was arrested and charged with possession of BC Powder – five months after she pled guilty to cocaine possession, finished her sentence, and returned home as a felon, the crime lab tested the substance and provided the results…

What about fertilizer?  

Drug Crimes Defense Lawyer in Myrtle Beach, SC

If police or prosecutors insist that a substance found on you was illegal drugs, and you know that it was not, don’t give up hope and don’t plead guilty.

You have the right to independent testing of the evidence against you, and we have access to the right experts for your case. In some cases, your charges will be dismissed once the state crime lab completes its testing, and there may be other defenses that are available to you.

Call me at 843-492-5449 or fill out our contact form to set up a free consultation to discuss your case.

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