Deceptively Simple: Can Urine Samples from CLIA-Waived Urine Drug Screen Devices Be Reused for Confirmatory Testing?

Area of Science:

• Clinical Chemistry
• Forensic Toxicology
• Laboratory Medicine

Background:

• Many urine drug screen (UDS) devices are CLIA-waived, allowing direct urination into the device.
• Labeling advises confirmation of positive results, but reusing specimens may risk contamination or adsorption.
• Collecting separate samples for confirmation negates CLIA-waived convenience and poses patient challenges.

Purpose of the Study:

• To investigate the suitability of reusing urine from a NexScreen device for confirmatory drug testing.
• To assess potential specimen contamination from the UDS device.
• To evaluate drug adsorption by the UDS device materials.

Main Methods:

• Drug-free pooled urine was incubated in NexScreen cups to test for leaching.
• 14 analytes were spiked above cutoff levels, incubated in NexScreen cups, and tested for adsorption.
• Confirmatory testing was performed on all prepared specimens.

Main Results:

• Incubation in NexScreen cups did not contaminate drug-free samples.
• Recoveries for 11 of 14 spiked analytes were ≥95%.
• Minor adsorption was observed for buprenorphine (94%) and THC metabolite (87%), with all analytes remaining above confirmation cutoffs.

Conclusions:

• Urine collected in NexScreen cups can be used for confirmatory drug testing.
• The NexScreen device does not significantly contaminate specimens.
• Minimal drug adsorption by the device does not impede confirmatory testing.