Re: 24hr wee wee test
As suggested, it's best to double check with your own doctor on this but
my sister had the 24-hour test for urinary catecholamines (hormones) looking for possible adrenal gland problems and was told to avoid [for 2-3 days before the urine collection]:
Caffeine (coffee, tea, cocoa, and chocolate).
Bananas, walnuts, avocados, cheese, beer, and red wine. (they contain nitrogen substances and apparently it's advisable to avoid)
Vanilla extract. (don't know why!!)
Also, obviously your doctor should know if you are taking any over-the-counter meds or other prescribed meds he/she may not know about.