Elevation of serum and urinary carbohydrate antigen 19-9 in benign hydronephrosis

Objective: The aim of this study was to find out the predictive role of serum and urinary carbohydrate antigen 19-9 levels in benign hydronephrosis and whether these levels are helpful for differentiation of complete or partial urinary obstruction. Materials and methods: Fifty-four patients with, and 23 without, benign hydronephrosis were enrolled in this study. Serum and urinary carbohydrate antigen 19-9 were determined by the chemiluminescence enzyme immunometric assay method and these levels were correlated with clinical factors. Results: The mean serum (P < 0.0001) and urinary (P < 0.0001) carbohydrate antigen 19-9 and serum creatinine (P < 0.008) levels were significantly higher in the hydronephrosis group than the control group. There was significant correlation between serum and urinary carbohydrate antigen 19-9 levels in the hydronephrosis group (r = 0.639, P < 0.0001). In the hydronephrosis group, there were no significant differences between the serum creatinine, serum or urinary carbohydrate antigen 19-9 levels and the clinical features except symptom duration. The best cut-off value for the serum and urinary carbohydrate antigen 19-9 were found to be 4.84 U/mL and 29.35 U/mL, respectively. Conclusion: Serum and urinary carbohydrate antigen 19-9 levels correlated with each other, were significantly elevated in patients with hydronephrosis and did not predict complete urinary obstruction. Benign hydronephrosis should be considered in the differential diagnosis of carbohydrate antigen 19-9 increments, as this is what is of most importance in clinical practice. © 2006 Japanese Urological Association