Yes, it's possible. If you notice a color change, we recommend you monitor your cat's PrettyLitter to see if the color change persists. This is because cats are sensitive creatures and they can be affected by normal life events like a change in food, weather or short-term stress.
If color change persists after 24 to 48 hours, that's when we'd recommend taking your cat to your local Veterinarian.
Please also be aware that when PrettyLitter is at the end of its life cycle, it can become saturated and urine can pool at the bottom of the litter box. This concentration of saturated PrettyLitter can cause a reaction that changes the saturated litter “blue”. If you notice the litter is turning a slushy consistency along with a blue color, it may just be time to change your litter.