Assessing open circuit and short circuit defect levels in circuits implemented in state of the art ICs is difficult when using conventional test circuits, which are designed to assess continuity and isolation performance of simple structures based on individual design rules. Including circuit blocks from ICs in test circuits provides a more accurate assessment of defect levels expected in ICs using the circuit blocks. Open circuit defect levels may be assessed using continuity chains formed by serially linking continuity paths in the circuit blocks. Short circuit defect levels may be assessed by using parallel isolation test structures formed by linking isolated conductive elements in parallel to buses. Forming isolation connections on a high metal level enables location of shorted elements using voltage contrast on partially deprocessed or partially fabricated test circuits.