Disclosed herein is a system for determining discontinuities in a blister pack. The system includes a blister pack and a discontinuity sensing apparatus coupled to the blister pack. The blister pack includes a tray with a plurality of cells and a seal layer arranged to seal the cells. The discontinuity sensing apparatus includes a signal generation element and a signal receiving element. In one embodiment, the signal generation element is arranged to transmit an acoustic pulse. In another embodiment, the signal generation element is arranged to transmit a swept acoustic signal. In one embodiment, the discontinuity sensing apparatus is coupled to the blister pack such that each of the plurality of cells is positioned at a unique distance from the discontinuity sensing apparatus. The determinations on discontinuities can be made in part from information from the time domain and/or in part from information from the frequency domain.