Can urinary biomarkers succeed diagnostic value of renal scintigraphy in patients with ureteropelvic junction disruption?

Introduction: The aim of this study is to evaluate the efficacy of urinary biomarkers as an easy to use, cost-effective and noninvasive alternative to renal scan for assessment of obstruction in patients with unilateral ureteropelvic junction disruption. Patients and Methods: The study included 39 patients diagnosed with unilateral ureteropelvic junction disruption. Patients were divided into 2 groups according to diuretic half-time in renal scan. There were 15 cases with obstruction, and 24 patients had non-obstructive dilatation. Cystatin C, β2-microglobulin, KIM-1, MCP-1, osteopontin and NGAL markers were analysed in urine samples. Hence the current data regarding the clinical usage of these markers is insufficient, ROC curves were formed to estimate cut-off values and detect marker's ability to distinguish obstruction. Two cut-off points were defined by ROC for Cystatin C, β2 microglobulin and MCP-1. Sensivity, specificity, positive and negative predictive values were obtained for each curve cut-off point. Results: Sensivity values to detect obstruction were 80% for Cystatin C, 80% for β2 microglobulin, 86,7% for MCP-1 and 80% for osteopontin. MCP-1 has obtained 73,3% sensivity, 62,5% specificity and β2 microglobulin has obtained 60% sensivity, 83,3% specificity in their second cut-off point. Conclusion: Cystatin C, β2-microglobulin and MCP-1 have high sensivity to assess obstruction. However, Cystatin-C and osteopontin have yielded lower specificities in the cut-off point with high sensitivity. Although it would be early to render a decision without the support of further clinical investigation, we believe MCP-1 and β2-microglobulin may have their appliction as non-invasive clinical tests in the future.