Abstract
A colorimeter capable of measuring results of enzyme-linked immunosorbent assay (ELISA) reactions directly in the wells of a microtiter plate is described. This colorimeter is as accurate as a conventional spectrophotometer in assessing ELISA reactions but had the advantage of not requiring transfer of the specimen to a separate chamber. With this colorimeter, 96 specimens can be read in approximately 5 min. A practical colorimeter such as this can make the use of ELISA tests more feasible for many laboratories.