<prompt> Anuria is defined as urine output less than4mlhr8mlhr12mlhr16mlhr  <response>: Anuria is nonpassage of urine, in practice is defined as passage of less than 100milliliters of urine in a day. Anuria is often caused by failure in the function of kidneys. It may also occur because of some severe obstruction like kidney stones or tumours. It may occur with end stage renal disease. It is a more extreme reduction than oliguria hypouresis, with 100 mLday being the conventional albeit slightly arbitrary cutoff point between the two Ref Harrison20th edition pg 277 