FABP1 and Patent ductus arteriosus: At 21 days, all 3/3 neonates with spontaneously resolved PDA had normal u-LFABP levels while 1/1 and 5/5 neonates who received IV PCT 1 cycle and IV PCT 2-3 cycles all had abnormal u-LFABP levels, respectively (p=0.011).