<unk>  is analogous to urinalysis on a community scale. Small molecule compounds consumed by an individual can be excreted in the urine and/or feces in the form of the unchanged parent compound or a metabolite. In communities with sewerage, this urine combines with other wastes including other individuals' urine as they travel to a municipal<unk>  treatment plant. The<unk>  is sampled at the plant's inlet, prior to treatment. This is typically done with autosampler devices that collect 24-hour flow or temporally composite samples. These samples contain biomarkers from all the people contributing to a catchment. Collected samples are sent to a laboratory, where analytical chemistry techniques (such as liquid chromatography-mass spectrometry) are used to quantify compounds of interest. These results can be expressed in per capita loads<unk>  on the volume of<unk> . Per capita daily consumption of a chemical of interest (e.g. a drug) is determined as where R is the concentration of a residue in a<unk>  sample, F is the volume of<unk>  that the sample represents, C is a correction factor which reflects the average mass and molar excretion fraction of a parent drug or a metabolite, and P is the number of people in a<unk>  catchment. Variations or modifications may be made to C to account for other factors such as the degradation of a chemical during its transport in the sewer system.
Wastewater-based epidemiology
Computational epidemiology
Spatial epidemiology
Epidemiology in Country Practice
Economic epidemiology
Real world data
Analysis of clinical trials
Diagnosis-related group