Abstract: A method for determining a state of a cell, the cell being placed in a sample, in contact with a culture medium, the method comprising: illuminating the sample with a light source and acquiring an image of the sample with an image sensor, the image sensor lying in a detection plane; from the acquired image, locating a position of the cell in a plane parallel to the detection plane; the method further comprising: from the acquired image, estimating a refractive index of the cell or a relative refractive index of the cell, the relative refractive index corresponding to a refractive index of the cell relative to the refractive index of the culture medium; from the estimation of the refractive index or of the relative refractive index, determining an index of interest of the cell; from the index of interest, classifying a state of the cell among predetermined states, the predetermined states comprising at least one apoptosis state and one living state.