Automated Solid Phase Extraction of THC and Metabolites from Whole Blood using the Gilson GX-274 ASPEC™

Tetrahydrocannabinol (THC) is the principle active component in marijuana. It is rapidly absorbed by inhalation and also through the gastrointestinal tract. Being stored in the fat tissue of the body, it is released over a long period of time. THC is metabolized into two main analytes: 11‐OH‐THC (11‐hydroxy‐THC) and 11‐Nor‐9‐carboxy‐THC (THC‐COOH).
Positive identification of tetrahydrocannabinol is commonly performed through screening tests using a urine sample, with confirmatory tests performed using mostly urine and blood samples. Urine analysis does have a false positive problem with a known drug Protonix™ which is used to treat gastroesophageal reflux disease (GERD). 4 Blood testing is commonly performed to detect the recent use of THC, and therefore is commonly used to investigate accidents and suspicion of driving under the influence (DUI) because blood testing can provide an indication of whether the subject was actually under the influence. Studies have shown that high THC blood levels are correlated with impaired driving.