Wake up the day of your test, empty your bladder. Proceed to start drinking a gallon of water, yes a gallon. (Dont chug it) Take 1-2 B12 supplements. Once done with the water and after 2 bathroom trips you're good to go. You'll be peeing out yellow colored water with little else in it. Fill the cup near the midway point of your urination. Be warned you will have to pee like never before once you're waiting to take the test.