Test structures and method for detecting defects using the same. A probe-able voltage contrast (VC) comb test structure that includes first, second and third probe pads, a comb-like structure including grounded tines, floating tines between the grounded tines, switching devices coupled with an end portion of each floating tine, and connecting the floating tines to the second probe pad, and the third probe pad being a control pad which controls the switching devices. A probe-able VC serpentine test structure that includes first, second, third and fourth probe pads, a comb-like structure including grounded tines, floating tines between the grounded tines and each floating tine connected together between the second and third probe pads, switching devices connected to an end portion of each floating tine and connecting the floating tines to the second and third probe pads, and the fourth probe pad being a control pad which controls the switching devices.