Résumé : A kinetic lattice gas model is set up to study nonequilibrium effects in thermal desorption caused by limited mobility in the adsorbate. Treating the theoretical desorption spectra as input data we show that nonequilibrium effects must show up when different types of Arrhenius analyses, such as threshold and isosteric methods, are applied. We obtain estimates of the lateral NO interaction energies. The theory developed here has broader applicability beyond the present system.