Phase I: mentioned that test is validated but no validation data availablePhase II overlap healthy—AKI risk—AKIPhase III—Se & Spbest cut off value S Cystatin C 0.53 mg/L with Se 0.64, Sp 0.85, PPV 0.44, NPV 0.94; best cut off value U Cystatin C 0.20 mg/L with Se 0.82, Sp 0.85, PPV 0.50, NPV 0.96More effective detecting negative than positive results. The gene discussed is CST3; the disease is acute kidney injury.