Blind trials of an onsite saliva drug test for marijuana and opiates

The objective of these clinical trials was to calculate the performance, limit of detection, specificity and sensitivity of a novel, semi-quantitative immunoassay for drugs of abuse in saliva and to determine operator bias when measured blind by four different operators. The test is based on lateral flow gold particle technology coupled with digital photography to provide a semi-quantitative end point. The performance of the test was compared with that of enzyme immunoassays and GC/MS methods. Volunteers consumed marijuana or codeine and their saliva was collected 0.25 to 24 h later with the Cozart RapiScan collection device. The sensitivity and specificity of the opiate test were both 100%+/-10.4% for codeine for 9 h after dosing. The cutoff of the marijuana test at 10 ng/mL THCA was too high to detect marijuana use for more than a few hours after smoking. There was no operator bias because the results were presented in written form either as "positive" or "negative" for each of the five drug classes on the screen of the hand-held reader.