CST3 and chronic kidney disease: To test this hypothesis, the study aims to measure serum cystatin C and creatinine levels in both patients with CKD and controls, compare eGFR values derived from cystatin C- and creatinine-based equations, evaluate the correlations of cystatin C with creatinine and eGFR, and ultimately determine the utility of cystatin C as an alternative biomarker for early CKD detection in the Indian population.