For cells, cell lines and tissues in culture till half confluency.A microtiter plate (spelled Microtiter is a registered trade name in the United States) or microplate or micro well plate or multiwell, is a flat plate with multiple "wells" used as small test tubes. The microplate has become a standard tool in analytical research and clinical diagnostic testing laboratories. A very common usage is in the enzyme-linked immunosorbent assay (ELISA), the basis of most modern medical diagnostic testing in humans and animals. A microplate typically has 6, 24, 96, 384 or 1536 sample wells arranged in a 23 rectangular matrix. Some microplates have even been manufactured with 3456 or 9600 wells, and an "array tape" product has been developed that provides a continuous strip of microplates embossed on a flexible plastic tape.