To safely pass a drug test synthetic is the only 100% way to go.Read the directions and practice with it. You can heat it up numerous times.
I've used it.It depends on whether I KNOW I'm clean or not.If I KNOW I'm clean I'll use my own piss if I'm not sure I use quickfix.I get hit with randoms(or supposedly randoms) a lot.But I tend to be pretty vocal about the drug war.