Last night (December 15) in B.C., 13 people died of a suspected drug overdose.

The unprecedented number prompted the B.C. Coroners Service to issue an “urgent” warning for drug users, asking them to exercise extreme caution, especially in Vancouver’s Downtown Eastside.

“We are not sure what has caused this very distressing spike in fatalities,” chief coroner Lisa Lapointe said in that release. “It will take detailed toxicology testing and further investigation to try to determine that.”

It could be some time before authorities are able to determine exactly what killed so many people in such a short period.

Since 2011, B.C.’s illicit-drug supply has become increasingly adulterated with fentanyl, a potent synthetic opioid that authorities have found in 60 percent of people who died of an overdose this year.

As the Straight reported on December 13, the recent surge in deaths over and above the increase that fentanyl has brought has prompted authorities to acknowledge that something has changed.

Interviewed for that story, Barb McLintock, a spokesperson for the B.C. Coroners Service, said that “about 10” deaths that occurred in the past four months “looked like a drug overdose” but toxicology reports came back negative for drugs such as heroin, fentanyl, and cocaine.

“We have a few cases…in which we have what appears to be a drug overdose—as in the scene looks like a drug-overdose death—but the first round of toxicology hasn’t come back positive for a drug overdose,” she said.

That could mean that what killed those people—and, possibly, the people who died last night—is carfentanil, a synthetic opioid similar to fentanyl but approximately 100 times more toxic.

In a telephone interview, Dr. William Schreiber, medical director of the Provincial Toxicology Centre, told the Straight that testing for carfentanil is far more complicated than many people might think.

“I wish that we looked like the people in CSI, I wish we had their work hours, and I wish we got paid like they do, but it’s not quite the same,” he said.

Schreiber noted that the Provincial Toxicology Centre, where the coroners service sends samples from suspected overdoses, presently does not know how to test for it.

He said it will likely be “two to three months” before the lab can develop such a process and put it into routine use.

Schreiber explained there is a combination of bureaucratic and scientific hurdles to overcome.

First, the Provincial Toxicology Centre needed permission to possess carfentanil. It only received federal consent to do so last week. The next step was to obtain a sample of the drug, which is sometimes used to tranquilize elephants. Interviewed yesterday (December 15), Schreiber said he hoped that a raw sample would arrive any day now.

“That’s actually the limiting step, for many labs,” he said, “is getting the pure drug so that you can develop a test that is reliable.”

Step three is where things get complicated.

“We are going to be looking for fairly small amounts of this compound, and we’re going to be looking for it in blood,” he said. “Blood is a very complex mixture. It is full of cells, it is full of proteins, it is full of all kinds of small molecules as well—things that we need to live—and we need to be able to detect just a very tiny amount of carfentanil in this mixture of stuff that has much greater amounts of other chemicals. And we need to have a test that will allow us to see it specifically.”

That involves first crafting a procedure for extracting carfentanil from the liquids carrying it, and then designing a test that can reliably confirm whether or not that substance that was extracted is, indeed, carfentanil.

“It’s chemistry,” Schreiber said.

It's also highly unlikely that testing strips that are currently the subject of a trial at Vancouver's Insite facility will be able to detect carfentanil.

Last September, the Straight reported that the strips, available at Insite for free, are a cheap and easy way for drug users to test if substances they purchased as heroin or cocaine contain fentanyl.

The company supplying the strips to Insite's operator, Vancouver Coastal Health, is Ontario-based BTNX Inc. On the phone from Markham, the company’s president and CEO, Iqbal Sunderani, said they have never tried detecting for carfentanil. But based on how the chemistry involved works, Sunderani said, it is doubtful the strips can identify it.

"I don't think that our test could pick that up," he said. "We reckon we could develop one. But we would need help with funding. Carfentanil, for us to outlay a research project just based on this, it would be exorbitant for us to absorb."

According to the latest trial data supplied by Vancouver Coastal Health, 82 percent of substances purchased as heroin tested positive for fentanyl from July 7 to October 31. For all drugs, that number is 80 percent.

During the first 10 months of 2016, 622 people in B.C. died of an illicit-drug overdose. That’s up from 510 in 2015 and 370 the year before.

On November 29, the Vancouver Police Department confirmed that carfentanil had been detected near the body of a man who had died in East Vancouver two weeks earlier. That test was conducted at a lab in Ottawa and involved a raw substance as opposed to a blood analysis.

Given the number of deaths the coroners service now suspects are overdoses but which tested negative for drugs, Schreiber said he does think carfentanil was involved.

“This would be an educated guess, but I think the answer is yes,” he said.