Uremia is a term use to loosely describe the illness accompanying kidney failure (also called renal failure). In kidney failure, urea and other waste products, which are normally excreted into the urine, are retained in the blood. Early symptoms include anorexia and lethargy, and late symptoms can include decreased mental acuity and coma. It is usually diagnosed in kidney dialysis patients when the glomerular filtration rate, a measure of kidney function, is below 50% of normal.