In March, Colorado became the first state in the nation to implement reforms to address wrongful arrests caused by unreliable field drug tests. Other states should follow suit to better protect the thousands of citizens falsely implicated and prosecuted by such tests each year.
More than half of the roughly 1.5 million drug arrests conducted in the United States each year involve colorimetric field drug tests, which use color-changing chemical reagents to detect the presence of illicit substances. These tests are fast and inexpensive, and they often serve as probable cause for arrest. However, they are also notoriously unreliable, with research identifying error rates as high as 38% in some contexts. Even test kit manufacturers warn that confirmatory laboratory testing is necessary.
A 2024 report by the Quattrone Center for the Fair Administration of Justice at the University of Pennsylvania Carey Law School estimated that approximately 30,000 people are falsely implicated by colorimetric field drug tests each year. That conservative estimate would make these tests the largest known cause of wrongful arrests and convictions in the United States.
Substances as commonplace as vitamins, soap, sugar, and even bird droppings have triggered false positive results. Because 95% of criminal cases are resolved through plea bargaining, and because 89% of prosecutors surveyed by the Quattrone Center reported that they accept guilty pleas without confirmatory laboratory testing, many individuals who are innocent of drug possession plead guilty in the face of an ostensibly positive field test result.
Colorado’s House Bill 26-1020, signed into law by Gov. Jared Polis on March 27, requires that when a colorimetric field drug test was used to test for the presence of a controlled substance and a person is solely suspected of low-level drug possession or a municipal drug possession charge, a police officer shall issue a summons rather than arrest the person. Without this protection, individuals whose cases rest entirely on the result of an unreliable test could face immediate custody, leading to employment disruption, separation from family, and mounting pressure to plead guilty rather than contest the charges from a jail cell.
The new law also requires trial courts to issue a formal advisement before accepting a plea from any person charged with drug possession when a colorimetric field drug test was used. The requirement applies across the full range of possession offenses, from the lowest misdemeanors through felony-level possession of larger quantities. The advisement must inform the defendant that colorimetric field drug tests are subject to false positive results, that such test results are inadmissible in court, and that the defendant has the right to enter a not guilty plea and request drug testing from an accredited forensic laboratory.
In 2025, the Colorado General Assembly passed House Bill 25-1183, which established a working group to study the use of colorimetric field drug tests across criminal proceedings and correctional settings. The working group, which included prosecutors, defense attorneys, forensic scientists, and corrections officials, submitted its findings and recommendations to the legislature in December 2025. Only four of Colorado’s 23 judicial district attorneys responded to its survey, though all four confirmed that field test results are only sent to a laboratory for confirmation when a case proceeds to trial.
The working group also examined the use of colorimetric tests inside Colorado’s prisons, where correctional staff administer the same tests to identify suspected contraband. The Colorado Department of Corrections reported a false positive rate of approximately 33% for its colorimetric test results, with unconfirmed positives routinely serving as the basis for disciplinary sanctions including transfers to higher-security housing and the loss of earned time credits.
HB 26-1020 was subsequently introduced on Jan. 14, 2026, by state Reps. Jennifer Bacon (D-7) and Lindsay Gilchrist (D-8) and state Sens. Matt Ball (D-31) and Lisa Frizell (R-2), and the bill reflected the working group’s core recommendations. It received unanimous support in both chambers
Reason Foundation contributed to the legislative discussion of HB 26-1020 through testimony before the House Judiciary Committee and educational outreach throughout the legislative process. In our testimony, we argued that the costs of colorimetric testing errors outweigh their benefits because they force innocent people to face an impossible choice between asserting their innocence from a jail cell or pleading guilty to crimes they did not commit.
By requiring summons in lieu of arrest for low-level drug possession cases that rely on colorimetric testing and by ensuring that defendants are informed of the limitations of these tests before entering a plea, HB 26-1020 is a meaningful and carefully targeted reform. The law’s unanimous bipartisan support reflects a growing recognition across the political spectrum that criminal justice processes should rest on reliable evidence. Other states confronting the same well-documented risks posed by colorimetric field drug tests can look to Colorado as a model for how to protect individuals from wrongful arrest and conviction while preserving the tools that law enforcement needs to maintain public safety.