Lab-based evaluation of first- and second-generation gamma-hydroxybutyrate test strips and pads in beverages.

Gamma hydroxybutyrate (GHB) has been used as a drug to facilitate sexual assault. Commercial testing devices are available for bars and patrons to test drinks that may have been spiked with GHB. In this study, six first-generation GHB test devices were evaluated for the detection of GHB at 0.8, 1.6, 3.2, and 16 mg/mL in beverages containing rum, vodka, beer, sucrose, and red wine. These strips used bromocresol green, a dye-binding reagent. Two second-generation test devices that use gamma hydroxybutyric dehydrogenase, a reagent with high GHB specificity, were also evaluated. GHB at 0.10, 0.25, and 0.50 mg/mL was spiked into the above beverages plus orange juice, whiskey, and Diet Coke®. Prepared separately, water spiked with GHB was used as a positive control and unspiked beverages as negative controls. Two individuals conducted the preliminary tests on all devices and were unblinded to the drink composition. Four other individuals blinded to the final contents were asked to test a subset of these samples. There was complete concordance between the results of tests conducted by blinded individuals. Two first-generation products were insensitive to GHB at 16 mg/mL. The remaining first-generation tests produced positive results between 3.2 and 16 mg/mL. Colored beverages (whiskey, beer, and red wine) produced colors that interfered with reading some tests. Second-generation tests produced positive results at 0.5 mg/mL and were the most sensitive. In conclusion, the endpoints of these newer tests were superior to first-generation devices and sufficient to detect GHB at concentrations that could cause untoward effects.