Once you are keto-adaptive, roughly 3 weeks in, you do not have excess ketones spilling out into your urine. (Sounds bad but is a natural process in the body) That original period of adaptation is why, if you test during that time, and the reading shows a stronger level of ketosis, that is because its reading what is in your urine at that time. My advice is spend your money on water enhancers, branch chain amino acids, or a product you would like to try, don't waste it on keto strips.