HD DIGITAL DISPLAY: 0.0-1.9ppm (No ketosis), 2.0-3.9 ppm (early ketosis), 4.0 -9.9 ppm (Light Ketosis), 10-39ppm (Stable Fat Burning Zone), 40-59ppm (Caution-High Ketosis), 60-99ppm (Ketoacidosis). 0 ~ 1.9 PPM: You are not in ketosis or just right before ketosis.