Two years ago, Minnesotans who carried thin strips of paper for detecting whether street drugs contain fentanyl could be arrested and charged with possession of drug paraphernalia.

Now, those paper strips — no more than a few inches long — have emerged as a vital tool in the state's fight to prevent opioid overdoses, which continue to claim hundreds of lives in Minnesota each year.

Nonprofit community groups and health clinics have given away more than 100,000 of the fentanyl test strips since Minnesota legalized them in July 2021.

The strips are already changing user behavior: The vast majority of people who discover fentanyl in their drugs using the strips have taken steps to reduce the risks of a deadly overdose, according to surveys by Minnesota providers.

The Steve Rummler Hope Network, the state's largest provider of free fentanyl test kits, has surveyed 722 people who have used the strips since October 2021. Of these, 90% said they changed their behavior to reduce overdose risk. Some 31% of respondents said they decided not to use the drug, while 23% chose to increase safety by using in a group or with another person. Others said they took smaller doses or slowed their drug intake, according to the participant survey.

Those findings are consistent with a smaller survey by NorthPoint Health and Wellness Center in north Minneapolis, which found that 89% of test strip users took overdose-prevention measures once they discovered fentanyl.

"Fentanyl test strips are gold," said Dr. Charles Reznikoff, an addiction medicine doctor with Hennepin Healthcare, who hands out the strips to many of his patients. "It not only saves lives, it serves as a reminder to the person that fentanyl may be present in whatever drug they may be using and is deadly."

A surge in fatal overdoses has heightened the urgency of efforts to distribute the test strips.

In 2021, overdose fatalities reached 1,286 — up 22% from the previous year and the highest in at least the past decade. Through an analysis of death certificates, the Minnesota Department of Health found that fentanyl — a synthetic opioid up to 50 times stronger than heroin — was involved in 90% of all deaths linked to opioid use that year. Because it is cheap, potent and plentiful, fentanyl is being mixed into a growing number of opioids to produce a stronger high.

The fentanyl test strips are part of a broader approach known as harm reduction, which seeks to give people tools to reduce their risk of dying or contracting infectious disease rather than emphasizing abstinence.

The paper strips work much like over-the-counter pregnancy tests. Each strip is dipped into a small amount of water containing a bit of drug residue. After a couple of minutes, either one or two red lines appear on the strip. One line means the liquid contains fentanyl; two lines means the test did not detect the drug. The strips can detect fentanyl in all types of drugs, including heroin, cocaine and counterfeit pain pills, and in different forms (pills, powder, and injectables).

"One reason the fentanyl test strips are so useful is there is a full-tilt industry of producing fentanyl, and right now it's humming," Reznikoff said. "There's a ton of [fentanyl], and that's why it keeps being put in all these different [drugs] and keeps killing people."

On a blizzardy morning, Gabe Lyrek, a harm reduction specialist, demonstrated how the strips work from the NorthPoint's harm reduction and testing services center in north Minneapolis, which provides the strips and other tools free of charge.

Slowly, Lyrek poured a tiny amount of sterile water from a test kit into an aluminum cup, sometimes called a "cooker" by drug users. Then he sprinkled in a sample of vitamin C powder — no more than the diameter of a pencil — into the cup and stirred it carefully. He then dipped the wavy end of the paper test strip into the mixture and waited 15 seconds before removing it. Within two minutes, the paper showed two pink lines — a negative result — confirming that fentanyl was not in the sample.

Lyrek and his team at NorthPoint have handed out more than 2,700 of the test strips since they were decriminalized — the most of any on-site location in the state.

"Once you know there's fentanyl in [the sample], then you can make an informed decision," Lyrek explained. "You can use slower. You can use less. You can dilute your drugs more. But there are always other options once you find out … that can prevent you from overdosing."

Staff at the NorthPoint harm reduction and testing services center are reminded daily of the high stakes of their efforts to educate users about the benefits of the test strips and other harm-reduction tools such as sterile syringes.

About two months ago, a woman overdosed and was no longer breathing in a church parking lot adjacent to the center at 710 W. Broadway. When she was discovered by security guards, Lyrek and others rushed outside to help. It took mouth-to-mouth resuscitation and five doses of Narcan, a drug that reverses the effects of opioids, to revive the woman.

"It's scary, because every time someone walks in here, that might be the last time you see that person," Lyrek said. "That's why we really try to develop relationships with people and let them know we care."

The need for fentanyl test kits has become so intense that it's now possible to buy them through Amazon.com and have them delivered to one's doorstep. While harm reduction specialists praise the growing availability of the strips, they encourage one-on-one visits to clinics and testing centers where they are available. Every time a fentanyl test kit is handed out, clinicians say, is another opportunity to talk to users about the deadly risks of fentanyl and ways to avoid overdosing.

"Out of everything that we provide here, the most important thing of all is the fact that we care about you," Lyrek said. "You don't know our name. We don't know your name. But the second you walk in that door, you have somebody who cares whether you live or die."

Staff writer Kim Hyatt contributed to this report.