Validity and reliability of in-person and remote oral fluids drug testing compared to urine drug testing

Increased telehealth use has led to greater interest in remote drug testing. The speed, acceptability, and ability to observe oral fluids testing makes it the best candidate for remote drug testing, but its validity and reliability compared to gold-standard urine drug testing have not been established.

Veterans (N = 99) recruited from mental health clinics completed in-person and remote oral fluids testing and in-person urine drug testing. The validity of oral fluids versus urine drug testing and reliability of in-person versus remote oral fluids testing were evaluated.

Validity of oral fluids testing was similar for samples collected in-person and virtually. Oral fluids testing had good specificity (0.93-1.00) and negative predictive value (0.85-1.00), but lower sensitivity and positive predictive value. Sensitivity (0.21-0.93) was highest for methadone and oxycodone, followed by cocaine and then amphetamine and opiates. Positive predictive value (0.14-1.00) was highest for cocaine, opiates, and methadone, followed by oxycodone and then amphetamine. Validity for cannabis was low, likely because of differences in detection windows for oral fluids versus urine drug screens. Reliability of remote oral fluids testing was adequate for opiates, cocaine, and methadone, but not oxycodone, amphetamine, or cannabis.

Oral fluids testing identifies most negative, but not most positive, drug test results. While oral fluids testing is appropriate in some circumstances, its limitations should be acknowledged. Remote drug testing addresses many barriers, but also generates new barriers related to self-administration and remote interpretation. Limitations include a small sample and low base rates for some drugs.