This is the first post in an ongoing discussion of harmful, wasteful, and useless practices.
Just seeing this list brought to mind all the times I have seen drug screens used to support judgmental and severely cognitively biased decision making. And it made me angry to think about the implications of this testing.
For further illustration, consider this vivid example from Stellpflug, Cole, and Greller:
“The test does not discriminate; if there is a physical interaction, it turns positive, regardless of whether the interaction is truly with the drug of concern. For example, the amphetamine portion of a UDS (typically designed to actually detect amphetamine) can result positive in the presence of pseudoephedrine or phenylephrine. The PCP (targeting PCP) screen can result positive by reacting with dextromethorphan. The tetrahydrocannabinol (THC) screen can be made positive by some nonsteroidal anti-inflammatory drugs (in laboratories without up-to-date capabilities), as the TCA screen commonly turns positive in the presence of diphenhydramine and other similarly structured drugs, and the cocaine screen can turn positive with the ingestion of coca tea. These examples culminate in an odd scenario in which someone aggressively treating a cold could feasibly have a UDS “positive” for amphetamines, cocaine, opioids, PCP, THC, and TCAs.”
The authors go on in the paper to state “False positives, false negatives, broad time frame of detection, and delayed confirmation all make the UDS inapplicable to real-time clinical decision making.”
The calculus is not improved in the ICU. The UDS almost never provides actionable information and serves to bias our opinion of the patient and their clinical syndrome.
A few examples of the ways this testing can lead us astray:
- “The UDS is positive for [X], so we can stop looking for causes of the encephalopathy”
- “They’re probably just delirious because they haven’t had [X] in a while, it was on their admission UDS”
- “UDS was negative, I doubt this was a toxidrome at all”
- “If we start them on this medication, will they even follow-up? Their UDS was positive for THC”
Bad data is worse than no data. I’m struggling to remember a time when a UDS had a net positive impact in the care of a patient.
If ordering a UDS is a common practice for you, I ask you to reflect on the risk:benefit ratio and whether it makes sense at all.