Thread by @MedEdPGH

It’s time for #PhysioQuizzo! And today, we got a really trippy puzzle for you. [thread]

1/x You’re still working in the ICU (1 week to go!), and you take care of a pt who overdosed. He was revived in the ER. Urine was obtained before naloxone was given.

Quiz on post 3/x.

2/x His UDS is shown below. His outpatient med list is also shown.

You’ll note his UDS is positive for everything...

3/x

Here’s the Quiz:
—Which of the following is the least he could have plausibly taken given his UDS? (Assume he’s taken all his home meds that day)

A. Each and every drug on the UDS
B. Home meds, ethanol
C. Home meds, EtOH, oxycodone, valium
D. Home meds, cocaine, oxy, heroin

4/ #PhysioQuizzo

Great job on the quiz guys. The majority did not get the answer correctly, but that just means we can have fun talking about the solution. First our main references:

emcrit.org/toxhound/uds-a…

ncbi.nlm.nih.gov/m/pubmed/24986…

5/ #PhysioQuizzo

Context: so this is a question about false positive values on the UDS. More precisely, it’s about the cross-reactivity of immune-based assays.

Point #1: cocaine is cocaine. Only rare cross reactivity. Rare.

6/ #PhysioQuizzo

Point #2: oxycodone is synthetic. “Opiates” are for opium derivatives.

-Oxycodone doesn’t show up as an opiate on a UDS. Naloxone does.

-No oxy, but positive opiates means taking something else: heroin, codeine, morphine.

7/ #PhysioQuizzo

Point #3: many things cross react with the assay.

Here’s a graphic made by someone else on twitter (let me know who and I’ll tag them!!), but for our quiz we used...

Ibuprofen for THC. Trazadone for amphetamines. Sertraline for benzos.