Its main aim was to reveal new synthetic recreational drugs as they hit the drug scene, and to help agencies tackle them faster.
It has proven a success, revealing a rise in cases of one particular drug, ethylone, along with traces of synthetic cathinones better known as bath salts.
"There's a whole new world of substances out there," said ESR's forensic toxicology and pharmaceuticals manager Mary-Jane McCarthy.
"It's very interesting, because we can use what we find through Customs and police data to correlate the information.
"The idea is that we can detect and identify these new drugs before we end up having deaths and investigations into what caused them."
Tracking these new drugs also assisted EDs and toxicologists with treatment.
"It's a huge challenge for clinicians when somebody presents to an emergency department with certain symptoms which they know don't look like meth, yet the patients are still having seizures or being in zombie states," she said.
"We can identify what's in the person, and then develop a database of clinical symptoms that can be turned into treatment options."
Not enough was known, for instance, around what the best treatment was for the cardiac effects of synthetic cannabinoids.
The most prevalent of them was AMB-FUBINACA, a drug not seen here before 2016 and notorious for inducing zombie-like behaviour.
It was reported to be 75 times more powerful than the THC in cannabis plants.
Others floating around the streets include 5Cl-AB-PINACA, 5F-ADB, 5F-MDMB-PICA, BB-22, CUMYL CYB7AICA, MMB-CHMICA and NM-2201.
"Not only are we seeing more of them, they're so toxic, as well."
McCarthy hoped to see more EDs joining the USED programme, in which patients whose data was processed would have to give their consent.
Those patients would not be identifiable to ESR or anyone outside of the DHB, and results would be sent back to the ED for follow-up patient care.
Dr John Bonning, chairman of the Australasian College for Emergency Medicine's New Zealand faculty, saw the programme as important for science, but questioned whether it would make a difference for front-line ED doctors.
"It's laudable from an epidemiology perspective, but it will not affect the management of the patient at that time," said Bonning, the clinical director of Waikato Hospital's ED.
The USED programme is part of ESR's wider "Border to Grave" drug surveillance activities, which identify new synthetic drugs as they enter New Zealand and track their real-time use in the community.