The present disclosure describes a method of detecting a drug marker in urine a urine sample using a toilet. The drug markers are fluorophores each of which emits a unique fluorescence spectra. Accordingly, the method does not detect the drug but rather, the drug marker. The drug marker may include quantum dots which may be functionalized by connecting the quantum dot to a biomolecule. The biomolecule may be cleavable by a peptidase, a protease, or a nuclease to release the drug. Alternatively, the composition may include a liposome carrier. A user who has consumed the drug composition urinates into the toilet and a urine sample is captured. The toilet includes a mechanism for fluid handling which diverts urine into a fluorescence spectrometer. The fluorescence spectrometer screens the urine for drug markers based on their unique fluorescent spectra.