Yannetti | Criminal Defense Law Firm | Boston, Salem & Dedham Massachusetts
Call For A Free Phone Consultation
Photo of the legal professionals at The Yannetti Criminal Defense Law Firm

Former Prosecutors, Aggressively Fighting For You

Photo of the legal professionals at The Yannetti Criminal Defense Law Firm

The Problems With Field Drug Tests

For decades, police officers have used field drug tests while detaining suspects to determine whether a substance is an illegal narcotic. These tests are inexpensive, costing roughly $2 each, and are seemingly easy to use. In most field tests, a police officer deposits a portion of the substance in question into a vial of pink liquid. If the liquid turns blue, the substance is considered to be an illegal drug. While these tests are not admissible in court, law enforcement agents often use these tests as evidence to support an arrest.

Unfortunately, however, these tests are problematic for many reasons, the biggest being the issue of false positives. According to a recent New York Times Magazine article entitled, How a $2 Roadside Drug Test Sends Innocent People to Jail, labs across the United States have found disturbingly high rates of false positives in field drug tests.

There are many potential reasons for these errors. For example, many police officers are not properly trained on how to conduct these tests. In addition, certain types of chemicals, such as household cleaners or acne medication, can create false positives. In the end, however, it doesn’t matter how the errors occur. False positives in field drug tests can unjustifiably wreak havoc on a person’s life.

Nevertheless, police officers often use these tests to justify an initial arrest, and even if a person is later exonerated, the humiliation and anguish of an unjustified arrest is a major infringement on a person’s rights. In the worst case scenario, the results, (often false) may be used to gain leverage over a defendant in an attempt to extract a guilty plea.

Field drug tests are not admissible in court and in fact, defendants have protections against these types of tests. In Massachusetts, for example, any substance being evaluated to be an illegal drug must be tested in a licensed laboratory. Furthermore, it is no longer permissible for the prosecution to merely introduce a lab certificate to prove that a substance is in fact an illegal narcotic. Instead, defendants have the right to cross-examine the lab technician who performed the test. The United States Supreme Court case of Melendez-Diaz vs. Massachusetts confirmed this right.

The many issues and problems surrounding these types of tests in connection with a drug arrest highlight the critical necessity of a person accused of a drug crime to retain the services of a knowledgeable attorney.

Sources: How a $2 Roadside Drug Test Sends Innocent People to Jail, The New York Times Magazine, By Ryan Gabrielson and Topher Sanders, Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009)


Client Testimonials

5 Star

In the most painful times in our lives–David, Greg and Lisa showed us their professional best–dignified, warm, gracious. David and his team will not let you down, you will be taken well care of and most importantly superbly and justly represented…
Barbara Lynch

Oh my goodness David is a miracle worker! Unbelievable results! David is so highly respected by attorneys and judges and prosecutors that he really makes an impact in court and presented our friend in the best possible light…

Jude Dasilva

Greg Johnson and David Yannetti are simply the best. After having two other attorneys on a case, I hired them and got results where others failed. They work hard for you and I highly recommend them!…

Vivian Trinh

If it was not for Mr. Yannetti I could have lost my career and opportunity to come back to USA again given that I am not a US citizen. Thank you Mr. Yannetti for all you did for me and my family. You and your office were truly there for me in my darkest hour…

Ajit Gupta

Greg Johnson is a charming attorney and seems to truly care about his client’s and the outcome of their case. If you ever need an experienced criminal defense Lawyer, Yannetti Criminal Defense Law Firm is the one to call!…


“I’ve got your back,” he told me early on. David did not disappoint. By showing up with David in the courtroom, I felt I’d made a clear statement of intent. The case was duly dropped…

James Brooks

Martindale-Hubbell | AV | Preeminent | Peer Rated for Highest Level of Professional Excellence | 2020
Best Lawyers | Best Law Firms | U.S. News | 2022
Avvo | 10.0 | Superb | Top Attorney Criminal Defense
Super Lawyers
Fox News | Criminal Defense Analyst
CNN | Criminal Defense Analyst
ID | Investigation Discovery | Consultant
Massachusetts | Lawyers Weekly | Criminal Defense Expert