Worldwide anthropogenic activities result in the production and release of poten-tially damaging toxic pollutants into ecosystems, thereby jeopardizing their health and continuity. Research studies and biomonitoring programs attend to this emerging problematic by applying and developing statistically relevant indexes that integrate complex biomarker response data to provide an holistic approach reflecting toxically induced alterations at the organism’s or population level. Ultimately, indexes allow simple result communication, enhancing policy makers understanding, so contributing for better resource and environmental managing policies. In this study three indexes , the Integrated Biomarker Response index (IBR), the Bioeffects Assessment Index (BAI) and the Principal Components Analysis (PCA), were evaluated for their sensitivity in revealing toxically induced stress patterns in cells of the diatom Phaeodactylum tricornutum under contaminant exposure. The set of biomarkers selected for index construction comprise the anti-oxidant enzymes APX, CAT and SOD, and the lipid peroxidation marker TBARS. Several significant inverse correlations with the concentration gradients applied, , was noticed for all indexes, though, the IBR excels for its reliability in delivering statistically significant dose-response patterns for four out of the five compounds tested.