In the 20 patients who developed AKI by creatinine criteria, both serum and urine NGAL levels rose significantly within 2 hours of surgery (mean urine NGAL rose from 1.6 ug/L to 147 ug/L while serum NGAL rose from 3.2 ug/L to 61 ug/L). Here, LCN2 is linked to acute kidney injury.