Cystatin С – a marker for early kidney damage

General Medicine, 2025, 27(4), 10-14.

D. Genov

Clinic of Nephrology, UMHAT “Sv. Ivan Rilski”, Department of Internal Medicine, Medical Faculty, MU – Sofia

Abstract. Background: Chronic kidney disease (CKD) is a global health problem with high morbidity and mortality. Novel biomarkers for early diagnosis and monitoring of kidney damage have been researched. Aim: To evaluate the role of serum CysC in detecting early renal impairment among CKD patients. Materials and Methods: This study included 207 CKD patients hospitalized at the Clinic of Nephrology, UMHAT “Sv. Ivan Rilski”, between May 2018 and February 2021. Medical history was taken, and physical examinations, hematological, biochemical and urine tests, 24-hour proteinuria and abdominal ultrasound scans were performed. CysC was measured using the enzyme-linked immunosorbent assay (ELISA) method. Results: The mean age of the patients was 56.81 ± 14.24 years; 108 (52.2%) were female. A moderate positive correlation was found between CKD duration and CysC (r = 0.294, p < 0.001). CysC correlated positively with uric acid (r = 0.363, p < 0.001), potassium (r = 0.305, p < 0.001) and proteinuria (r = 0.364, p < 0.001) and negatively with calcium (r = -0.274, p < 0.001) and albumin (r = -0.363, p < 0.001). There were significant positive correlations between CysC, phosphorus (r = 0.423, p < 0.001) and parathyroid hormone (PTH) (r = 0.477, p < 0.001). Significant negative correlations were found with hemoglobin (r = -0.578, p < 0.001), hematocrit (r = -0.535, p < 0.001) and erythrocytes (r = -0.588, p < 0.001). A high positive correlation was found between CysC and urea (r = 0.785, p < 0.001). There was a very high positive correlation with serum creatinine (r = 0.808, p < 0.001) and negative – with estimated glomerular filtration rate (eGFR; r = -0.822, p < 0.001). Conclusion: CysC is a reliable and sensitive biomarker for the detection of kidney function decline in CKD. It can be successfully used as a diagnostic biomarker for early renal damage.

Key words: cystatin C, chronic kidney disease, kidney damage, biomarkers, renal function

Address for correspondence: Dr. Diyan Genov, MD, ORCID: 0009-0002-9872-5693, e-mail: dian.genov@abv.bg