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 cytotoxicity of materials. The reproducibility of the MTT test has been studied in this paper in three ways. First, the reproducibility of MTT assay itself 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 significant differences were found with non-random sampling but no differences were found with random sampling. The third part examined the stability of the optical density of the solution read by a spectrophotometer and its dependence on temperature. The stability of the optical density was examined at room temperature and 4-degrees-C. Plates were maintained at these temperatures between readings. The optical density of dissolved formazan solution was compared by analysing the result with 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.