December 2022

In the October issue we discussed the growing concerns regarding a potential increase of cannabis-impaired drivers, how Long-term sequelae of substance use disorder from adolescence through adulthood and how Medication-Assisted Treatment (MAT) can provide guiding principles in criminal justice settings. 

Did you know that when you submit your questions to Let's Talk Tox you are getting your questions answered by Toxicology expert Pat Pizzo? Don't sweat! Each question remains completely anonymous so you don't have to share your information with some random strangers on the internet! So what are you waiting for? Submit your questions below!

Pat Pizzo

Toxicology resources at your finger tips! 

Email us your questions for Pat and they’ll be answered in a future issue of the Let’s Talk Tox newsletter!

You asked, Pat answered! 

Find out the answers below to questions your peers submitted! Each question is answered to help provide you with resources and tools to combat issues clinicians face day-to-day.

The answers reflect the views of Pat Pizzo and not necessarily those of Thermo Fisher Scientific.

"An immunoassay urine test will often give positive results for not only fentanyl and its metabolite norfentanyl, but many of the fentanyl analogs. Laboratories normally only confirm for fentanyl and its metabolite norfentanyl. Many labs also offer extended fentanyl testing – meaning fentanyl analogs. If you are doing the initial screen, you will need to check the package insert for the reagents or on-site test cup you use to determine what you are testing. If you do not do the initial (screening) test you will need to check with the lab you use to see exactly what drugs are included in the screen and confirmation. 

Cut off levels for screening are usually 1 ng/mL confirmation cut off levels vary so check with your confirmation lab. How long it is detected is dependent on the usage type of a person. Single use 3 days for fentanyl and 4 days for norfentanyl. Chronic use up to 19 days for fentanyl and 26 days for norfentanyl."

Find solutions that fit your testing needs for Fentanyl here

“Determining reuse is not an easy task and better left to experts. You must have at least 2 specimens and you absolutely must normalize the values. You cannot use a value as ng/mL to determine reuse or residual elimination. Clearance is determined by usage type. Various papers have shown clearance for social users at 5 days and chronic at 30 using a 15 ng/mL cut off. If you go below 15 ng/mL the detection times are extended.”

Access information for THC Reagents here.

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Drugs of Abuse Testing matrices; urine, oral fluid, specimen validity and automated drug testing, as well as SAMHSA guidelines. Find out more

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