Urine discoloration usually means that your urine is darker than usual or cloudy.
Blood in the urine is a completely different side effect and can be very serious. Call your doctor right away if you have blood in your urine.
If you're having sentinel lymph node dissection surgery, you may have a blue dye injected into your system so your doctor can trace the path of lymph fluid. Right after the surgery, your urine may have a blue tint. This is completely normal and usually goes away in a day or so.
Some multivitamins can make your urine darker. This is nothing to worry about.
If you're dehydrated, your urine is usually darker. Read tips on managing dehydration.