The problem of modifying a synthesized circuit to improve its path sensitizability has been investigated. It is shown that a large number of paths, that cannot be sensitized using single-transition tests, are redundant paths and they can be removed by appropriate modification of the circuit. The effect of these modifications on area and performance of the circuit has been analyzed. For the paths which are neither redundant nor sensitizable using single-transition tests, it is shown that they can be sensitized using multiple-transition tests. Results obtained on some common benchmark examples suggest the validity and viability of this approach.