Occasionally, ghost shrimp aren't as clear as we feel like they should be, but generally that creamy whiteness means that it's towards the end.
sometimes it just appears to mean that they are stressed, probably from the ride home. Give it a day or so... I neglect my shrimps for a couple of days when I bring them home. Then, whoever is still alive goes in the tanks, and whoever isn't goes back to the pet store (I figure if there's multiple bodies, the problem came from there).
I leave them in the tank, as long as they're still behaving normally, patrolling and eating and all. But if they start randomly bouncing about (like they're having seizures), or sitting there twitching their legs, or just hanging on, I pull 'em out.