Tag: DUI blood test

THC Metabolite Concentration is Inconsistent Predictor of Impairment

Are blood or saliva concentrations of delta-9 THC metabolites predictive of impairment? That’s what a recent article in the Neuroscience and Biobehavioral Reviews journal sought to determine. The article published data from a meta-regression analysis of 28 studies involving 824 participants. The biggest takeaway is that neither THC nor THC metabolite concentrations are consistent predictors of impairment.  Surprisingly, THC levels in blood, which is the bodily specimen of choice in OWI search warrants in Iowa, showed the weakest correlation. Iowa law equates the mere presence of inactive metabolites of THC with being under the influence of cannabis.  However, the science […]

Read More

Should Hospitals Refuse to Comply with Blood Draw Warrants?

There is a growing trend in Iowa when it comes to OWI investigations, particularly those involving drugs other than alcohol. Peace officers are bypassing the standard implied consent procedures and seeking search warrants for blood instead. It’s not just for situations involving deaths or potentially fatal injuries.  Yes, there’s a law authorizing search warrants in those specific situations.  We’re talking here about regular, vanilla OWI traffic stops.  The run of the mill variety that happen every day across the state. Police have the discretion to apply for general search warrants even for ordinary cases if they want a blood sample […]

Read More

THC Levels Do Not Predict Driving Impairment

The February 5, 2021 issue of Traffic Injury Prevention published results from an Australian study assessing the relationship between THC levels and driving performance.   Volunteers consumed vaporized cannabis samples of varying potencies containing THC, CBD and a placebo.  Blood and saliva samples were collected 30 minutes after inhalation and 3.5 hours later.  Researchers evaluated driving performance on a simulator. Nearly half of the participants failed to show driving impairment after 30 minutes despite showing THC levels above the per se limits, e.g., 5 ng/ml.  Several participants did show impairment at the 3.5 hour mark, but their THC levels were below […]

Read More

THC Metabolites Remain in Blood for Extended Periods During Abstinence

According to data recently published in the journal Drug and Alcohol Dependence, THC remained detectable in blood at levels greater than 2.0 ng/ml during several days of abstinence. Investigators affiliated with the University of British Columbia reviewed the relevant literature assessing residual THC plasma levels in those who regularly consume cannabis.  They reported: “[I]n all studies where participants were observed for over a day, blood THC [levels] in some participants remained detectable during several days of abstinence,” with some subjects continuing to test positive for up to 30 days. Some subjects also demonstrated a so-called “double hump” pattern “where their […]

Read More

Yes, Drug Testing Methods Can Mistake Hemp-Derived CBD for THC

I recently came across a little-known study published in the Journal of Analytical Toxicology that raises serious questions regarding whether the gold standard in forensic urine testing could mistake hemp-derived CBD for THC. Many laboratories include derivatization as a part of their sample preparation for analysis by gas chromatography – mass spectroscopy (GC-MS).  Derivatization is the process by which a compound is changed chemically so that it has properties that are more amenable to a particular analytical method.  Essentially, the new compound becomes more suitable for detection and analysis. Researchers discovered trifluoracetic anhydride (TFAA), a common derivatizing agent used in GC-MS […]

Read More