There's a chapter (siman) of Shulchan Aruch devoted to this — but a short one. Orach Chayim 166 reads:
Some say that one need not be careful lest he interrupt between washing hands and saying the blessing over bread; others say he must be careful. It's good to be careful. And if he waited the time it takes to walk twenty-two ama (cubits), that's called an interruption.
Mishna B'rura clarifies that the first opinion agrees an interruption is forbidden if it occupies one mind, taking it away from the purity of his hands, and that the second opinion agrees that an interruption is okay if it's needed for the meal. [Thus, the difference between the two opinions is in the case of an interruption that doesn't heavily occupy the mind but isn't needed for the meal.]
We see, then, that an interruption needed for the meal is fine; and kidush obviously is for the meal (MB 271:61).
 But MB cites authorities that say that, even so, one should ideally be as quick as possible. See there for more details, too.