A STUDY OF THE REPRODUCIBILITY OF THE MTT TEST

The MTT test has been widely used as a rapid and sensitive method for screening anticancer drugs as well as for the assessment of cytotoxici ty of materials. The reproducibility of the MTT test has been studied in this paper in three ways. First, the reproducibility of MTT assay i tself has been investigated. The comparisons were performed within the plate, between plates as well as between flasks of the cultured cells . The Student's t-test was used to analyse the data and statistically significant differences were found for all the groups compared. Second , the influence of random sampling was investigated. Statistically sig nificant differences were found with non-random sampling but no differ ences were found with random sampling. The third part examined the sta bility of the optical density of the solution read by a spectrophotome ter and its dependence on temperature. The stability of the optical de nsity was examined at room temperature and 4-degrees-C. Plates were ma intained at these temperatures between readings. The optical density o f dissolved formazan solution was compared by analysing the result wit h ONEWAY and statistically significant differences were found for the group of data at room temperature while no differences were shown for the group of data at 4-degrees-C.