Analyses of beverage remains in drug rape cases revealing drug residues--the possibility of contamination from drug concentrated oral fluid or oral cavity contained tablets.

In drug-facilitated sexual assault (DFSA) cases, drug residues may be detected in beverage remains found in cups or glasses known to have been used by the victims. In this small naturalistic study, the possibility of beverages being contaminated, either by drug concentrated oral fluid or by oral cavity contained tablets, was investigated. Analysis of residues from cups containing soft drinks was performed by immunoassay and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Beverage with both added tablets and spiked oral fluid was investigated, as well as simulation of swallowing tablets. Only the residues from added tablets were positive with immunoassay, while drugs were detectable in all cups using more sensitive UPLC-MS/MS. In conclusion, the possibility of detecting drug residues in beverages due to a contamination, from either drug concentrated oral fluid or oral cavity contained tablets at a time of consumption, should be kept in mind when performing sensitive analysis.