Some test their heroin before taking it

The newest tool in the fight against opioid overdoses is an inexpensive test strip that can help heroin users detect a potentially deadly contaminant in their drugs.

Sales of fentanyl test strips have exploded as a growing number of overdose-prevention programs hand them out to people who use illicit drugs.

Though they weren’t designed for it, the test strips can signal the presence of fentanyl in illicit drugs. Some health officials question their accuracy, but they have proven to be so popular that some programs can’t get enough to satisfy demand.

“As soon as I hit the street with them, they’re gone,” said Washington, D.C., needle-exchange outreach worker Maurice Abbey-Bey.

The U.S. is in the midst of the deadliest drug overdose epidemic in its history, and it’s been getting worse. More than 70,000 Americans died of drug overdoses last year, a 10 percent increase from the year before, according to preliminary U.S. government numbers.

Growing numbers of recent deaths have been attributed to the painkiller fentanyl and fentanyllike drugs. The drugs are far more potent than heroin, but they are relatively cheap and increasingly have been cut by suppliers into street drugs without buyers’ knowledge.

The strips sell for $1 each. Costs can quickly add up for groups distributing them because some people use drugs four or five times a day.

Government agencies have begun paying for the test strips and providing them to needle-exchange programs. The state health department in California started last year, and the health departments in some cities — including Philadelphia and Columbus, Ohio — have started since then.

But some other health agencies have declined, citing uneasiness with the tests’ accuracy or doubt about whether someone would actually throw away contaminated dope.

There’s been little research on whether tests strips are an effective weapon against the overdose epidemic, said Catherine McGowan, an assistant professor at the London School of Hygiene and Tropical Medicine.

“Anything that empowers people who inject drugs to mitigate their own risk is a good thing,” McGowan said. “You just need to be really careful.”