Assuming this was the WISC-IV, and not the new WISC-V, it is possible that the score you were given was an extended IQ score, which could most certainly be as high as 173 (though very, very few children will score that high!). I assume your child is six years old, in which case there is plenty of ceiling in the extended norms for the possibility of a score in this range.
160 is the maximum IQ score using the standard norms. The maximum ExIQ is 210.
What the score means is that your child is exceptional, even among the extremely bright.
Oh, and you belong here...
