Substitution Quick Question

Substituting a friends urine 20 min. before the test, have the temperature and disposale problems figured out.

Only question, can they identify between urines? I have sent my own clean urine in before, but recently smoked again so using a friends. Just want to make sure, i'd rather test dirty than get caught for substitution.

They cannot determine anything but whether or not the urine is clean. Make sure your friend is clean of any drugs including prescriptions or your screwed. This is why most of us here use Quick Fix.