The Beckman Coulter AU400 Chemistry System, formerly the Olympus AU400 has over 85 tests with a maximum throughput of 400 tests per hour. The AU series systems are critically acclaimed open-reagent, high-quality chemical systems that are considered to be among the most popular on the market, especially in the US laboratory market. Chemical analyzers create anomalous patterns by measuring substances in body fluids. The wide range of tests can be grouped into the following categories: electrolytes, enzymes, blood glucose, metabolites, thyroid, hormones, lipids, therapeutic drug monitoring, and drug of abuse monitoring. This analysis can be performed on blood (whole blood, serum or plasma), urine, semen or cerebrospinal fluid. Chemical analysis begins by placing patient samples in individual capsules, test tubes, slides, or sample cups that are transported by conveyor belts in sample racks or carousels in reagent trays. Samples are sampled and then automatically mixed with diluents and reagents in reaction tubes. Reagents are removed from the reagent carousel, which is usually refrigerated to preserve the shelf life of the reagents longer. Reaction tubes are stored and processed in reaction carousels. The reaction carousel has mixing stations (to mix samples and reagents) and wash stations (to rinse test tubes). The tubes are made of glass or plastic, depending on the manufacturer, but must be optically clear so that light can pass through without any scratches or blemishes. Chemical analysis is calculated by the absorbance of specific wavelengths of light as it passes through the sample. All chemical analyzers have a photometer (filter photometer or spectrophotometer) that measures the light absorbance of the sample and calculates the result. Filter photometers use glass filters coated with colored material on a rotating filter wheel, while spectrophotometers use prisms or gratings to isolate these wavelengths from the scanner beam. In both cases, a lamp (usually halogen) is the light source. Spectrophotometry is a more commonly used method than filter photometry, which is currently only available in Johnson & Johnson, Roche Cobas and Siemens size systems. Spectraphometry is used in most other systems, including Abbott, Beckman and Roche Hitachi systems. The process of obtaining results from an absorbance test is classified as either endpoint or kinetics. Endpoint methods incubate the reaction mixture for a predetermined time to reach the endpoint or equilibrium of the reaction. Kinetic methods monitor the reaction as the reagent and sample are mixed, and then determine the rate of change in absorbance, which correlates to the analyte concentration. So kinetic energy is a way faster than the end.