A method of detecting loss of refrigerant within a cooling system of the type having a condenser, a refrigerant receiver in fluid communication with the condenser, a sensor configured to detect a level of refrigerant within the receiver, an evaporator in fluid communication with the receiver, and a pump or compressor in fluid communication with the evaporator and the condenser, includes establishing a baseline measurement of refrigerant mass contained in the receiver with the sensor during certain power loads applied to the cooling system, monitoring a mass of refrigerant in the receiver with the sensor at a certain power load applied to the cooling system, and identifying whether the monitored mass of refrigerant is less than the baseline measurement of refrigerant mass over a predetermined period of time. Systems for detecting loss of refrigerant are further disclosed.