Synthetic Oral Fluid Was Checked Against Native Human Specimens
The saliva assay used a synthetic matrix for calibration but also tested native human oral fluid. That comparison supplied evidence for using the surrogate rather than simply assuming that synthetic and authentic specimens behave identically.
The calibration matrix was defined
Sobolesky and colleagues described a blank matrix made from albumin in buffered solution mixed with extraction buffer. They assessed human drug-free oral-fluid specimens against that calibration system, including low-level fortified measurements. The panel measured ten cannabinoids and metabolites by LC–MS/MS.
The human-matrix challenge mattered
The report found no native-versus-synthetic matrix difference exceeding the stated 20% criterion in the evaluated specimens. Qualitative infusion experiments also examined signals during injections of ten individual blank oral-fluid samples. These experiments are different from the small three-person dosing illustration included elsewhere in the paper.
Keep the scope of comparability visible
Agreement in the tested specimens does not establish that every collection buffer, unusually composed specimen or instrument will behave the same way. The calibration matrix, specimen preparation and acceptance criteria are part of the method. This was analytical evidence supporting a measurement workflow; it did not validate a saliva concentration-to-dose relationship or demonstrate an individual’s impairment. A different surrogate matrix needs its own supporting comparison.
Related analysis: the oral-fluid assay’s small human illustration.
Research cited
Sobolesky and colleagues (2019). Validation of a liquid chromatography-tandem mass spectrometry method for analyzing cannabinoids in oral fluid. DOI: 10.1016/j.cca.2019.01.002.
