Structures for testing a field effect-transistor or Kelvin field-effect transistor, and methods of forming a structure for testing a field-effect transistor or Kelvin field-effect transistor. The structure includes a device-under-testing that has one or more source/drain regions and a first metallization level arranged over the device-under-testing. The first metallization level includes one or more first interconnect lines. The structure further includes a contact level having one or more first contacts arranged between the first metallization level and the device-under-testing. The one or more first contacts directly connect the one or more first interconnect lines with the one or more source/drain regions. The structure further includes a second metallization level arranged over the first metallization level. The second metallization level has a first test pad and one or more second interconnect lines connecting the one or more first interconnect lines with the first test pad.