Because there are many stages of chronic kidney disease, there are many symptoms which correspond to the different stages. Chronic kidney disease is divided into five different stages based the rate at which the glomerulus filter the blood per minute. This is referred to as the glomerular filteration rate (GFR), and reflects how well a persons kidneys are filtering his or her blood. Doctors can determine the GFR by studying the creatinine levels present in a blood test! A persons GFR is normal if it is greater than 90 m per minute. GFR is an accurate measure of how well a persons kidneys are functioning.