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friendly reminder that urine drug screens are bad tests, they miss a lot of things and a lot of common/benign medications can trigger false positives it's basically an EM boards question to NOT make clinical decisions based on UDS

I'm so so so thankful my doctor is the only person who has to review my state-mandated twice yearly urine screen and all she has to do is report "expected" or "unexpected" back to the state, because it took me several years to find that "Benadryl can pop as methadone"

She, thank god, would frown at it every time and say "I should figure out what's causing that false positive" and mark me compliant instead of accusing me of all kinds of shit based on The Infallible Test(tm)! It gave me the room to get curious and go find those papers!

they’re rarely, if ever, done in the UK and in my ICU days I never once thought “I could really use a tox screen to guide my management here”

poppy seed bagels tho. om nom nom

also of course posts ≠ medical advice "can make positive" ≠ "makes positive" and so forth

Idk if this is still true (or if it ever actually was) but every time urine drug tests come up I think about how you used to be told to avoid poppyseed muffins and bagels before them because they could trigger false positives for opiates

i would think so but also it was in an episode of seinfeld so maybe not

I work forensic inpatient psych. One of our patients had a + fentanyl UDS and I told them it was most likely a false, bc very few of our pts get to leave the fac. They tested everyone and we had 9 more + for fentanyl and/or meth. Nobody believed me until the quants came back negative for everyone.

It’s important to distinguish screening from confirmatory drug testing. Screens are rapid immunoassays that are sensitive, so a positive result is only presumptive and can reflect cross-reactivity. Confirmatory tests (GC-MS) are definitive. In many setting, a positive screen triggers confirmation.