A spot assay or spot test can also refer to a specific test in microbiology. This test is often used to check the growth rate of bacterial or yeast cells on different media or to perform serial dilution tests of micro-organisms. Usually a 96-pinner (often called frogger) is used to perform these spot assay.
Another application is high-throughput screening, whichoften uses spot assays to determine the growth of eg. mated cells or to check for protein-protein interactions in a yeast two-hybrid test. This is often done with a robot.