Embodiments of the present disclosure are configured to assess the severity of a blockage in a vessel and, in particular, a stenosis in a blood vessel. In some particular embodiments, the devices, systems, and methods of the present disclosure are configured to assess the severity of a stenosis in the coronary arteries without the administration of a hyperemic agent. In some embodiments, the devices, systems, and methods of the present disclosure are configured to assess a vessel by automatically correcting for drift in the equipment utilized to obtain measurements related to the vessel.