Abstract: Objective To investigate the changes of serum β2-microglobulin（β2-MG） and cystatin C （CysC） in evaluation of renal deficiency in newborns with hyperbilirubinemia. Methods 128 newborns with hyperbilirubinemia between January 2014 and June 2016 in Department of Pediatry in our hospital were selected and 76 were found with mild jaundice （256.5 μmol/L>TBIL≥221 μmol/L） and 52 with moderate/severe jaundice （TBIL≥256.5 μmol/L）. 60 age-and gender-matched newborns were chosen as healthy controls. The levels of serum urea nitrogen（BUN）,creatinin （sCr）,CysC,β2-MG were detected,and the changes of TBIL,BUN,sCr, CysC,β2-MG in children before and after treatment were compared among them. Results Out of 128 newborns with hyperbilirubinemia,the renal deficiency was found in 25 cases,including 20 in moderate/severe jaundice group and 5 in mild jaundice group;serum levels of BUN,sCr,CysC and β2-MG in moderate/severe group were （5.76±1.45） mmol/L,（52.35±17.16） μmol/L,（2.68±0.45） mg/L,（4.25±1.52） mg/L,respectively,which were significantly higher than those in control group[（4.20±1.06） mmol/L,（38.65±14.23） μmol/L,（0.92±0.25） mg/L,（2.15±1.24） mg/L,all P<0.01] or those in mild icteric group[（4.58±1.23） mmol/L,（43.76±15.75） μmol/L,（1.76±0.37） mg/L,（3.48±1.40） mg/L,all P<0.01];serum levels of CysC and β2-MG in mild icteric group were （1.76±0.37） mg/L and （3.48±1.40） mg/L,which were significantly higher than those in control group [（0.92±0.2） mg/L and （2.15±1.24） mg/L,respectively,both P<0.01];there was no significant difference as respect to serum BUN or sCr between the control and mild icteric group（P>0.05）;after treatment,serum bilirubin,BUN,sCr,CysC and β2-MG levels in newborns with hyperbilirubinemia were（182.42±45.25） μmol/L,（4.32±1.25） mmol/L,（45.24±14.35） μmol/L,（1.86±0.38） mg/L,（3.42±1.36） mg/L respectively,significantly lower than those before treatment[（278.65±68.46） μmol/L,（5.35±1.30） mmol/L,（50.56±16.25） μmol/L,（2.25±0.41） mg/L,（3.96±1.45） mg/L,all P<0.01]. Conclusion Severe hyperbilirubinemia can induce renal damage in newborns,however,the damage can be recovered after timely treatment. Serum β2-MG and CysC can be acted as sensitive indicators for diagnosis of early renal dysfunction in newborns with hyperbilirubinemia.

Key words: Hyperbilirubinemia, β2-microglobulin, Cystatin C, Renal damage, Newborns