This tool provides a toxicokinetics-toxicodynamics (TKTD) analysis of bioassay survival data, including descriptive summaries of the data and an estimation of LCx values (x% Lethal Concentration). MOSAICGUTS-fit does not expect any input besides the survival dataset: the service will optimize its parameters automatically.

All calculations are based on a companion R package named MORSE and more details about the underlying modeling can be found in the corresponding vignette and companion research papers.

New! MOSAICGUTS-fit is now recommended in the recent  Scientific Opinion from EFSA .
  • Jager T, Albert C, Preuss T, Ashauer R. 2011. General Unified Threshold Model of Survival-a Toxicokinetic-Toxicodynamic Framework for Ecotoxicology. Environmental Science and Technology, 45: 2529–2540. URL :

  • Delignette-Muller ML, Ruiz P, Veber P. 2017. Robust fit of toxicokinetic-toxicodynamic models using prior knowledge contained in the design of survival toxicity tests. Environmental Science and Technology, 51: 4038-4045. URL :

  • Baudrot V, Preux S, Ducrot V, Pavé A, Charles S. 2018. New insights to compare and choose TKTD models for survival based on an inter-laboratory study for Lymnaea stagnalis exposed to Cd. Environmental Science and Technology, doi: 10.1021/acs.est.7b05464. URL :

  • Jager T, Ashauer R. 2018. Modelling survival under chemical stress. A comprehensive guide to the GUTS framework. Version 1.0. Available from