Traffic Tech #241: Field Test Of On-Site Drug Detection Devices |
|---|
|
Recently, police agencies and researchers have begun to explore the use of on-site urine drug screening devices as a complement to psychophysical tests used by officers as part of the Drug Evaluation and Classification (DEC) program. The National Highway Traffic Safety Administration (NHTSA) sponsored a field test by ISA Associates and the University of Utah's Center for Human Toxicology (CHT) to determine the accuracy and usefulness of commercially available devices when used by trained police officers in field settings.
Five Devices Tested
Five commercially available on-site drug detection devices were selected based on objective criteria, such as price, single or multiple test panel, types of drugs tested, specimen handling, number of reagents, reaction time, reading time, analysis complexity, FDA clearance, rater confidence, and other factors.
TesTcup-5®, Roche Diagnostic Systems, Inc
TesTstik®,Roche Diagnostic Systems, Inc
Triage®, Biosite Diagnostics
AccuSign®, Princeton Biomedical Corporation
Rapid Drug Screen®, American Bio Medica Corp
Two police departments, Houston, Texas and Nassau County, New York, conducted the field tests. Both Nassau County and Houston had active DEC programs and both used a central testing facility to process DUI arrestees. Each site collected urine specimens from 400 arrestees. Data collection ran from November 1998 to November 1999 in Nassau County and from October 1998 through July 1999 in Houston.
Each urine specimen was tested with each of the five devices and the order of device testing rotated with each sample. A police officer performed the testing with the first device and a research analyst tested the remaining four devices. Each device tested for cannabinoids (marijuana), cocaine, amphetamines, opiates, and phencyclidine (PCP) at the screening cutoff concentrations in the 1992-1993 DOT/DHHS regulations.
For the Mass Spectrometry (MS) laboratory confirmation part of the study, additional drugs within each drug class were tested, and lower cutoff concentrations than recommended by DOT/DHHS were used. Officers also assessed each device on five elements (ease of use, time needed to conduct the test, need for specimen handling, readability of results, and usefulness of the test for routine DUI evaluation). If the urine sample tested positive for any of the five drugs on any of the five devices, the sample was sent to CHT for confirmation. In addition, five percent of the samples that tested negative were also sent for confirmation.
Results
More than one-third (36 percent) of the 800 cases tested positive for at least one of the five drugs on at least one of the devices. The on-site devices generally performed well when compared to each other. There was complete agreement among the devices in 91 percent of the cases.
The devices also performed well when compared to MS confirmations across all five drug classes. Table 1 compares the devices to the MS confirmations (conducted on 322 cases). It shows the false positive results, which were recorded when the device indicated a positive result, but no drug(s) or metabolites were detected in the MS confirmation at a sufficient concentration to explain the positive result. Table 2 shows the false negative results, where the device tested negative, but the sample contained the target drug at a concentration above the device screening cutoff. There were no false negatives on any device for the 34 samples that tested negative on all five devices for all five drugs. False negatives, however, were found on those samples that tested negative on some, but not all the devices.
Discussion
The use of on-site drug detection devices, such as those evaluated in this field test, provide supplemental information to law enforcement officers responsible for enforcing drug impaired driving laws. This field test compared the performance of the devices when used by law enforcement personnel and trained laboratory technicians. The devices generally performed well in the hands of law enforcement officers. Data indicate that, when cutoff concentrations and additional drugs are taken into consideration, the devices were accurate in identifying positive samples and rarely failed to identify a driver who had the target drugs in his or her urine. Overall error rates were low, but they were higher for the officers than for the research analysts. Additional
training and experience is recommended if the on-site devices are to be used routinely by law enforcement officers.
Potential device errors related to the MS confirmation concentration cutoff and the detection of drugs in addition to the standard DOT/DHHS battery suggest that lower concentrations should be considered and additional drugs included in the confirmation when testing samples collected from DUI drivers. Finally, the remarkably high drug positive rate found in this field test indicates the need for additional research to gain an accurate understanding of the prevalence of drug use in the impaired and general driving populations.
HOW TO ORDER
For a copy of Field Test of On-site Drug Detection Devices, (40 pgs plus appendices), write to Research and Traffic Records, NHTSA, NTS-31, 400 Seventh Street, S.W., Washington, DC 20590, fax(202)366-7096 or download www.nhtsa.dot.gov /people/injury prev/res&eval James F.Frank, Ph.D., was the contract manager.
|
|
Cocaine/BZE | Amphetamines** | Opiates*** | PCP | |
|---|---|---|---|---|---|
| Triage® | 0.00 | 0.00 | 1.75 | 0.12 | 0.62 |
| TesTcup® | 0.00 | 0.00 | 0.25 | 0.25 | 0.75 |
| AccuSign® | 0.25 | 0.12 | 0.25 | 0.25 | 1.50 |
| Rapid Drug Screen® | 0.12 | 0.12 | 0.25 | 0.25 | 0.75 |
| TesTstik® | 0.00 | 0.00 | 0.12 | 0.25 | 0.62 |
* Analytes not detected by MS ** Percentage adjusted for the presence of MDMA *** Percentage adjusted for the presence of hydromorphone/hydrocodone
| THC-COOH | Cocaine/BZE | Amphetamines | Opiates | PCP | |
|---|---|---|---|---|---|
| Triage® | 0.25 | 0.25 | 0.00 | 0.00 | 0.00 |
| TesTcup-5® | 0.25 | 0.00 | 0.00 | 0.12 | 0.25 |
| AccuSign® | 0.12 | 0.12 | 0.00 | 0.00 | 0.00 |
| Rapid Drug Screen® | 0.37 | 0.12 | 0.00 | 0.00 | 0.00 |
| TesTstik® | 0.25 | 0.12 | 0.00 | 0.00 | 0.00 |
U.S. Department of Transportation
National Highway Traffic Safety Administration
400 Seventh Street, S.W. NTS-31
Washington, DC 20590
If you would like to receive a copy contact: Linda Cosgrove, Ph.D., Editor, Evaluation Staff
Traffic Safety Programs
(202) 366-2759, fax (202) 366-7096
E-MAIL: lcosgrove@nhtsa.dot.gov