Nephropathy is one of the causes of premature deaths among diabetic patients. The alarming rise in the mortality rate of diabetics globally due to complications like, kidney diseases is the foremost concern of this undertaking. This study determined the serum levels of cystatin C in diabetic patients as an early marker of glomerular dysfunction. It sought to find if cystatin C, a low molecular weight plasma protein; which is normally being filtered by the glomeruli, totally reabsorbed and catabolized in the proximal convoluted tubule of the kidneys, can detect renal insufficiency earlier than urea nitrogen and serum creatinine. Beta 2-microglobulin (b2m), another protein in which plasma level is also being maintained by the kidneys, was included in this study. Pearson coefficient correlation was used forstatistical analysis. One hundred diabetic participants without renal dysfunction were selected by purposive sampling. A control group composed of non-diabetics with the same gender and age bracket as the test group was also included. Fasting blood glucose, urea nitrogen, serum creatinine, b2m and cystatin were measured using the reagents from Abbott Diagnostics and its equipment, the Architect c4000. Computed r-values of -0.118 (0.224) for fasting glucose and 0.195 (0.052) for urea nitrogen implied that the two parameters are not significantly related to the level of serum cystatin. However, computed r-value of 0.526 (0.000) for creatinine indicates that when creatinine level increases, cystatin also increases; while the 0.766 (0.000) for b2m showed that there is a great possibility that when b2m is elevated, the cystatin of diabetic patients is also high. Moreover, serum levels of cystatin were elevated in 27% of the total diabetic participants, while 19% have increased beta 2-microglobulin, that is, in the presence of normal blood urea nitrogen and serum creatinine. The findings suggested that serum cystatin C is a potential early marker for glomerular dysfunction in cases of incipient diabetic nephropathy, as seen in elevated levels of cystatin with concurrent normal levels of the routine kidney markers. Further, serum
cystatin is a superior renal marker compared to beta 2-microglobulin as shown in 27 diabetics with increased cystatin against 19 elevated b2m.