An isolation assembly for use with coiled tubing is described. The isolation assembly has a check valve for providing selective fluid communication through from the coiled tubing, through the isolation assembly, and into a downhole tool, such a straddle packer. The isolation assembly includes a shuttle moveable within a housing, and plurality of ports to selectively provide fluid communication from within the isolation assembly below the check valve, through the ports, and into the annulus, thus allowing selective surface-controlled equalization of downhole equipment. Also described is a bottom hole assembly including the isolation assembly. An improved method of fracing a formation includes providing a check valve, thus improving the life of the coiled tubing and the safety of the operation, and reducing the time to perform a given downhole operation.