SLC9A3 and acute kidney injury: In this population, levels of urinary NHE3 normalized for urine creatinine were increased six times as much in patients with ATN than in those with prerenal azotemia (0.78 +/− 0.36 vs. 0.12 +/− 0.08, p ≤ 0.001), while urinary NHE3 could not be detected in the 14 control ICU patients without ARF.