Recovery and Stability of Δ9-Tetrahydrocannabinol Using the Oral-Eze® Oral Fluid Collection System and Intercept® Oral Specimen Collection Device.

Abstract

Oral fluid (OF) is increasingly used for clinical, forensic and workplace drug testing as an alternative to urine. Uncertainties surrounding OF collection device performance, drug stability and testing reproducibility may be partially responsible for delays in the implementation of OF testing in regulated drug testing programs. Stability of Δ(9)-tetrahydrocannabinol (THC) fortified and authentic specimens was examined after routine collection, transport and laboratory testing. Acceptable recovery and stability were observed when THC-fortified OF (1.5 and 4.5 ng/mL) was applied to Oral-Eze devices. Neat OF samples collected with Oral-Eze, processed per the package insert, and fortified with THC (3 and 6 ng/mL) were stable (±20%) at room temperature (21-25°C), refrigerated (2-8°C) and frozen (-25 to -15°C) conditions up to 1 month, while samples collected with Intercept devices showed decreases at refrigerated and room temperatures. After long-term refrigerated or frozen storage, maximum reductions in THC concentrations were 42% for Oral-Eze and 69% for Intercept. After ≥1 year frozen storage, 80.7% of laboratory specimens positive for THC (3 ng/mL cut-off) by GC-MS were reconfirmed positive (within 25%), with an average THC decrease of 4.2%. Specimens (n = 47) processed with Oral-Eze (diluted) and tested via enzyme immunoassay were concordant with LC-MS-MS results and showed 100% sensitivity and 95% specificity. Paired specimens collected with Oral-Eze and Intercept exhibited 98% overall agreement between the immunoassay test systems. Collectively, these data demonstrate consistent and reproducible recovery and stability of THC in OF after collection, transport and laboratory testing using the Oral-Eze OF Collection System.