San Diego drivers facing a DUI stop may now be asked for something other than “license and registration” — officers have quietly added a handheld saliva analyzer to their toolkit to screen for recent drug use. The pocket-sized unit gives a simple positive-or-negative result for several drug categories in a matter of minutes, and the department has begun rolling it out to specially trained Drug Recognition Experts after starting the program in October.
How the roadside test works
The device, Abbott’s SoToxa Oral Fluid Mobile Test System, uses a saliva swab to screen for THC, cocaine, opiates, amphetamines, methamphetamine and benzodiazepines, and reports only whether a substance is present rather than a numeric level, according to Abbott. The company and other vendors say the unit can generate results in roughly five minutes, with any positive result in the field meant to be followed by a full laboratory confirmation test. Independent evaluations have found that the technology can be useful in flagging recent use, although sensitivity varies by drug type, particularly for benzodiazepines and some prescription medications, according to the Journal of Analytical Toxicology.
How San Diego is using the test
The San Diego Police Department bought five SoToxa units with a state grant backed by taxes on legal cannabis sales and has limited their use to officers certified as Drug Recognition Experts, according to the San Diego Union-Tribune. Officers told the paper they still lean on traditional field sobriety tests and their own observations before offering the saliva screen, and that the on scene SoToxa check is voluntary, with no immediate penalty if a driver declines. The Union-Tribune also described a traffic stop in which a driver who passed a breathalyzer later tested positive for methamphetamine on the SoToxa after acknowledging earlier use.
Legal context and blood draws
When a driver does test positive on the roadside screen, San Diego officers treat that result as probable cause to seek a blood sample, which remains the evidentiary standard in court. Blood testing, however, sits under tighter legal rules than breath testing. In Birchfield v. North Dakota, the U.S. Supreme Court held that officers may administer breath tests without a warrant in many DUI investigations, but that blood draws usually require one, and California courts have echoed that officers should obtain a warrant when time allows.
Other states have tried to spell out specific impairment thresholds. Colorado law, for example, allows a jury to draw a permissive inference of impairment at five nanograms of THC per milliliter of blood, showing how some states handle numeric drug limits, according to Colorado law. California does not currently have a comparable per se numeric limit for drugs and instead relies on its general impaired-driving statute, California Vehicle Code §23152.
Accuracy and evidence limits
Toxicology experts and law enforcement alike caution that finding a drug in saliva is not the same thing as proving a driver was legally impaired. Independent studies report strong performance for certain substances but clear gaps for others, especially benzodiazepines, and THC levels in oral fluid do not track cleanly with the kind of impairment standards courts are used to applying. A review of statewide oral fluid testing programs found accuracy rates above 80 percent for many drug targets, but lower sensitivity for some categories, according to the Journal of Analytical Toxicology. Manufacturers stress that any field-positive result should be backed up by secondary laboratory testing, and Abbott recommends that positive screens be confirmed with lab analysis…