Can using too much or too little pee affect the results?
Sometimes, yes. Too little urine and the test simply won’t work– the control line will not appear, because there will not be enough moisture to trigger the chemical reaction. Too much pee and you run the risk of over-saturating the test– in which case the control line will wash away. (See the importance of control lines now? 🙂 It is impossible to trigger a false positive simply by using too much or too little pee.
