In
renal physiology,
net acid excretion (
NAE) is the net amount of acid excreted in the
urine per unit time. Its value depends on urine flow rate, urine acid concentration, and the concentration of
bicarbonate in the urine (the loss of bicarbonate, a
buffering agent, is physiologically equivalent to a gain in acid). NAE is commonly expressed in units of
milliliters per
minute (ml/min) and is given by the following equation: