When a person experiences incontinence of any kind, the most essential step to assess, diagnose and treat the condition is to determine the basis for the problem. For patients who have urinary retention problems—meaning the inability to empty the bladder completely – post-void residual measurement is a way to evaluate the amount of urine remaining in the bladder once urination (or voiding) has occurred. The procedure is usually done within five to ten minutes after urination and can be done with a physical exam, an ultrasound or catheterization. If a patient has high post-void residual volume of urine left in the bladder, it could indicate a urinary tract infection, a renal deficiency or benign prostatic hyperplasia. The condition may also be caused by certain drugs or medications or by certain disorders such as multiple sclerosis, diabetes or Parkinson’s.