text:  We now have better drug tests. A new fentanyl sensor is more sensitive than any other electromechanical device available, according to research published in the journal Small. Fentanyl is one of the main reasons of overdose deaths in the U.S. and is often hidden in other drugs without the consumer's knowledge. This new portable sensor can tell the difference between fentanyl and other opioids with a 91% success rate.