Saliva can provide direct evidence that a drug or metabolite is present in that specimen. Using its concentration to estimate a blood value calls for a different validation.
The investigators developed a liquid chromatography method with diode-array detection for five antipsychotics, carbamazepine and selected metabolites. The laboratory reported linearity from 10 to 1,000 ng/mL for its analytes and applied the method to saliva collected from 40 treated people. The panel included carbamazepine-10,11-epoxide and the active risperidone metabolite 9-hydroxyrisperidone.
The calibration curve relates instrument response to concentration in saliva. It provides no conversion to an individual’s plasma concentration. In a case review, identify the matrix, collection time and whether the laboratory reported the parent drug, a metabolite or both. A plasma estimate or impairment opinion requires separate evidence beyond identification in saliva.
Saliva method study for antipsychotics, carbamazepine and their metabolites (full text) · DOI