Value of combined measurement of urine N-acetyl-beta-D-glucosaminidase activity and serum Cystatin C in diagnosing diabetic nephropathy in early phase / 中国医师进修杂志

ABSTRACT

Objective To explore the value of combined measurement of urine N-acetyl-beta-D-glucosaminidase (NAG) activity and serum Cystatin C in diagnosing diabetic nephropathy (DN) in early phase. Methods Sixty-two cases with type 2 diabetes (diabetic group) were divided into three groups according to their 24 hours urinary albumin excretion (24hUAE) : group A (normal albuminuria, 20 cases), group B (microalbuminuria, 22 cases) and group C (macroalbuminuria, 20 cases). Furthermore, 30 healthy people were involved in control group. 24hUAE,NAG,serum creatinine (SCr) and serum Cystatin C were measured, and endogenous creatinine clearance rate (Ccr) was calculated by Cockcroft-Gault formula. All these indexes among three groups were compared. Results The levels of urinary NAG activity and serum Cystafin C in diabetic group was significantly higher and Ccr was significantly lower than those in control group(P < 0.01). The levels of urinary NAG activity and serum cystatin C gradually increased in group A, B and C(P< 0.05 or < 0.01). While no significant difference was observed between group A and group B in the level of SCr (P > 0.05). There were significant positive correlations among the levels of urinary NAG activity, serum Cystatin C,24hUAE and SCr (P< 0.01),and all above showed negative correlations with Ccr (P<0.01). Co-detection of urinary NAG activity and serum Cystatin C had significantly higher positive rate [80.6%(50/62)] than single one [58.1%(36/62),61.3%(38/62)](P<0.05). Conclusion Co-detection of urinary NAG activity and serum Cystatin C may indicate early renal damage in DN, and it is valuable in diagnosing DN in early phase.