What is the difference between Insulation Resistance Testing and Dielectric Withstand Testing?

Although the the dielectric withstand test and the insulation resistance test are similar, insulation resistance tests generally run below 1000 Vdc and return a value in ohms, while dielectric withstand test voltages can run up to 5000 Vac and 6000 Vdc depending on the requirements and returns a value in milliamps.