A kidney viability assessment system (KVAS) is disclosed which provides objective and reliable tests to assess the viability of transplant or donor kidneys in vivo and predict their post-transplant outcomes. KVAS includes an optical device augmented by an intelligent algorithm that can evaluate the viability or quality of the donor kidney in a real-time, non-invasive way. In particular, it includes a handheld optical coherence tomography (OCT) imaging device and at least one processor configured for executing a set of instructions corresponding to an automatic image processing algorithm for quantification of kidney microstructures and functions. Handheld OCT can survey the entire surface of kidney, and the image processing algorithm automatically segments and quantifies the diameter and/or density of the kidney microstructures, blood flows, etc., and quantitative values are displayed in real-time on a display of the KVAS.