Abnormal renal physiology Impaired urinary acidification 2017-05-27T11:07:24Z Renal acidification defect The kidney contributes towards acid-base homeostasis by excreting H+ ions and retaining bicarbonate. This process is known as acidification of the urine. The pH of urine ranges normally from 4.5 to 8. The inability to reduce the pH of the urine in a situation where it would be otherwise expected is known as an acidification defect.