Rationale: Calculating glomerular filtration rate is the best way to determine kidney function. It is calculated with a formula that considers a client’s age, gender, race, and serum creatinine level. A GFR < 15 mL/min indicates stage 5, end-stage CKD. These clients require dialysis or kidney transplant for survival. A GFR of 15 to 29 indicates stage 4 kidney disease, and preparation for dialysis or transplant is usually indicated. Stages 1 – 3 of kidney disease are less severe and can often be managed with medication and lifestyle changes.