A non-destructive method and device for analyzing a sample comprising transparent living and/or dead cells, by 5 means of a digital holographic microscope, where the sample (8) is exposed to light from a laser (2). The light that travels through the cells in the sample will experience a difference in the optical path length compared to the surrounding media and the wave front that emerges from the 10 cells will thus be phase shifted. This distortion can be detected in the digital hologram, which is reconstructed from the interference pattern detected by a digital sensor (17), such as a CCD or a CMOS, as phase differences or phase shifts and thereby creating a digital hologram. The 15 phase shift of each element of the hologram is then used for analyzing the characteristics of the cells in the sample.