A forensic toxicologist at the lab who tested George Floyd’s blood said it was common for drunk driving suspects using fentanyl to have higher levels of the drug in their systems than Mr. Floyd did when he died. Prosecutors hoped his testimony would strike a blow at Derek Chauvin’s lawyer’s argument that Mr. Floyd’s death may have been an overdose.
The toxicologist, Dr. Daniel Isenschmid, works at NMS Labs in Pennsylvania and testified on the ninth day of the trial against Mr. Chauvin, who has been charged with murder in Floyd’s death. Of the more than 2,300 blood tests from drunk drivers that NMS Labs tested last year ̵
Prosecutors had called him to the stands to refute Mr. Chauvin’s lawyer that fentanyl, a strong opioid, had caused Mr. Floyds overdose. Prosecutors say Mr Chauvin is responsible for Mr Floyd’s death, and earlier Thursday a pulmonologist testified that Mr Chauvin’s knee on Mr Floyd’s neck and back were important factors in his death.
Dr. Isenschmid said that last year, in cases where NMS Labs tested blood from a person who had died and had taken fentanyl, the average amount that researchers found was 16.8 nanograms per day. Milliliters, approx. 50 percent higher than the amount found in Mr. Floyd’s blood. But Mr Chauvin’s lawyer, Eric J. Nelson, noted that the average was among people who died of any cause and had fentanyl in their system, not just overdoses. And, he pointed out that the average level of fentanyl among this group was slightly below Mr. Floyds.
The testimony of Dr. Isenschmid, who previously worked as chief toxicologist at Wayne County Medical Center in Detroit, was some of the most technical yet, but jurors seemed attentive, according to a courtroom journalist.
He said that when a person’s body processes fentanyl, it is converted to norfentanyl, and that Mr. Floyd had a relatively high proportion of norfentanyl, indicating that his body had already processed a significant portion of fentanyl. This strengthened the prosecution’s argument that Mr. Floyd had not overdosed; overdose with fentanyl often occurs shortly after taking the drug before a person’s body can break down much of the drug.
But Dr. Isenschmid admitted in response to Mr Nelson that it was also possible that Mr Floyd had taken and treated fentanyl earlier in the day and then taken more in moments before or during the arrest. Toxicological results, says Dr. Isenschmid, does not indicate when a certain amount of fentanyl was taken.
Mr. Nelson has pointed out that pills were found that had Mr. Floyd’s DNA, and which may have been partially ingested, in the back of the police car where Mr. Floyd map was placed.
Still, Dr. Isenschmid that the same amount of fentanyl can have very different effects in a new user as opposed to a person who is addicted to the drug. Mr. Floyd’s girlfriend has said that she and Mr. Floyd both fought to stop using opioids.
“If a person becomes tolerant of a drug, they need more and more to get the desired effect,” said Dr. Blacksmith.
Methamphetamine was also found in Floyd’s system, although Dr. Isenschmid said the levels were so low that it probably had no intoxicating effect.