.2 μg/L). There was a poor correlation between concentrations of both oxycodone and noroxycodone in plasma and saliva over a range of times following dosing (r                            (2) = 0.4641 and 0.3891, respectively). No correlation was shown between salivary pH and oxycodone or noroxycodone concentrations. The majority of patients questioned chose saliva sampling over plasma sampling as the preferred method.