How to get accurate ketone readings? 1. In order to get accurate ketone readings, please exhaust the residuals completely with the ketone meter before your first use by running the keto breath tester 3 times without blowing,because each ketone breath analyzer was tested during the production before shipping to warehouse, there maybe residuals; if you want to test another person consequently after your testing, please also kindly exhaust your previous residuals. 2. Please blow immediately within first 5 seconds when displaying BLOW on the ketosis tester if you finish the residuals exhaustion step, because the ketone breath tester starts analyzing the breath right after the first 5 seconds Ketosis Readings Instructions (ppm): 0 ~ 1.9 PPM: You are not in ketosis or just right before ketosis. 2.0 ~ 3.9 PPM: You are at very early stage of ketosis. 4.0 ~ 9.9 PPM: You are in a light status of ketosis. The body fat is burning at a low pace. 10 ~ 39 PPM: You are in the optimum level of ketosis. This is the stable fat burning zone, the process of fat being used by the body as the main source of energy. 40 ~ 59 PPM: Be Caution! You are approaching too much ketosis level. Adjust your leve Kind Reminder: Readings will be slightly different from the blood meter because of different analyzing methods. Please catch the same keto meter to track your own personal ketosis records, only in this way you can get your own changing status. Package Contains: 1 x portable ketone meter 10 x replaceable mouthpieces 1 x carrying string 1 x user manual 2*AAA Batteries are not included