If microscopy is necessary, the urine is first centrifuged to concentrate the solid elements so that they can be viewed more easily. A drop of the concentrated sample is placed under a coverslip and examined, typically at 10x and 40x magnification. If it is necessary to determine the exact number of cells or casts in the sample, it can be placed in a counting chamber called a hemocytometer. Urine is traditionally examined by light microscopy, but some laboratories use phase-contrast microscopes, which improve the visualization of elements such as urinary casts and mucus. There are also automated systems that use flowresensce flow cytometry technology and others with pattern recognition to identify microscopic elements in the urine.