A leftover drink can be tested as a physical specimen. Its result answers a different question from a blood or urine test.
Soltaninejad and colleagues prepared nonalcoholic soft drinks spiked with six benzodiazepines, then analyzed them with high-performance liquid chromatography and ultraviolet detection. They reported recoveries of 93.7% to 108.7% across their tests and calculated detection limits of 0.01 to 0.02 micrograms per milliliter. The validation concerned the tested compounds, drink matrices and analytical conditions.
A positive result can document an analyte in the submitted liquid. Connecting it to a person’s exposure requires information about the container, collection and storage, who consumed it, and the amount consumed. For a negative result, compare the laboratory’s panel and reporting limit with the suspected compound and the beverage’s composition. A method tested in spiked soft drinks does not automatically cover every mixed drink.