OBJECTIVE: To study the value of apolipoprotein H (apoH) gene expression in peripheral blood mononuclear cell (PBMC) and urinary N-Acetyl-beta-D-Glucosaminidase (NAG) and retinal-binding protein (RBP) in the early diagnosis of renal function damage in neonates. METHODS: Sixty sick neonates who renal function damage probably occurred were enrolled. The blood and urinary samples were collected twice within 48 hrs following admission, with an interval of 12-24 hrs. Expression of apoH gene in PBMC was determined with RT-PCR. The levels of blood urea nitrogen (BUN) and creatinine, and urinary activities of NAG and RBP were measured with enzymatic reaction. RESULTS: The abnormal rates of blood apoH and urinary NAG and RBP were 73.3%, 83.3% and 76.7%, respectively in the first detection. The second detection for blood apoH and urinary NAG and RBP showed abnormal rates of 70.0%, 66.7% and 76.7%, respectively. There were no significant differences in the abnormal rates between the three markers either in the first or the second detection (P>0.05). Beside there were no significant significances in the abnormal rates between urinary NAG and blood BUN in the second detection, the abnormal rates of blood apoH and urinary NAG and RBP in both detections were significantly higher than those of BUN or creatinine (P<0.01 or 0.05). CONCLUSIONS: There are identical values of blood apoH gene expression and urinary NAG and RBP in the early diagnosis of renal function damage in neonates. The above three markers are more sensitive to early renal function damage than blood BUN and creatitine.［Chin J Contemp Pediatr, 2009, 11 (8):649-652］