Chronic kidney disease (CKD) is divided into five stages, ranging from stage 1 to stage 5. Each stage is determined by a blood test known as the estimated glomerular filtration rate (eGFR), which establishes how well your kidneys filter waste and excess fluid from your blood. With each stage of CKD, the function of your kidneys progressively worsens and requires different treatments to slow down kidney damage and to keep them working for as long as possible.