Colorado has become the first state in the nation to prohibit arrests based solely on colorimetric drug tests, also known as field drug tests.

Last legislative session, lawmakers passed a bill establishing a working group to make recommendations regarding the use of colorimetric drug tests in criminal proceedings.

Colorimetric drug tests were used in about half of all drug tests nationwide, according to a 2025 study by the University of Pennsylvania.

To conduct these tests, the suspected substance is placed into a small bag and shaken. The bag contains chemical reagents that change color if an illicit substance is identified. Research has found false-positive rates as high as nearly 40% in certain cases, leading manufacturers of colorimetric tests to recommend that they be used only for presumptive purposes and not as a basis for arrest or conviction.

It’s estimated that about 300 Coloradans have been arrested on drug charges each year resulting from the tests’ use.

Recommendations from the task force led to House Bill 1020, sponsored by Reps. Lindsay Gilchrist, D-Denver, Assistant Majority Leader Jennifer Bacon, D-Denver, and Sens. Matt Ball, D-Denver, and Lisa Frizell, R-Castle Rock.

The bill prohibits law enforcement from arresting an individual for a Level 1 drug misdemeanor based solely on a positive colorimetric field drug test. It mandates authorities to issue a summons instead.

The bill also requires courts to issue an advisement stating that colorimetric tests have known error rates and informing defendants of their right to enter a not guilty plea and request a drug test from a forensic laboratory before accepting a plea.

The bill passed unanimously in both the House and Senate and was signed into law last month.

“This bipartisan win, passing with unanimous support of both the House and Senate, is an important step toward preventing wrongful arrests and convictions across the state,” said Gilchrist. “Assistant Majority Leader Bacon and I are grateful for the diverse group of stakeholders that came together to push this important law across the finish line.”