Kidney failure refers to a condition where the kidneys are no longer able to function properly. This means that they cannot filter waste products and excess fluids from the blood, leading to a buildup of toxins in the body. Kidney failure can be acute (sudden) or chronic (long-term). Acute kidney failure occurs suddenly and usually resolves after treatment, while chronic kidney failure is long-lasting and may eventually lead to end-stage renal disease if left untreated. Treatment options for kidney failure include dialysis, transplantation or supportive care depending on the severity of the condition.