Urinary and Serum Carbohydrate Antigen 19-9 as a Biomarker in Ureteropelvic Junction Obstruction in Children

Purpose: We evaluated the predictive role of serum and urinary carbohydrate antigen 19-9 in the diagnosis and followup of pediatric ureteropelvic junction obstruction. Materials and Methods: The study included 27 children with ureteropelvic junction obstruction who underwent pyeloplasty (group 1), and 41 controls consisting of 27 healthy children (group 2) and 14 children with hydrocele/renal cyst (group 3). Serum and voided urine were evaluated for carbohydrate antigen 19-9 in each group. Additionally urine from the affected pelvis and fluid in hydrocele/renal cyst were collected at surgery in groups 1 and 3. Serum and voided urine samples were obtained at 3, 6 and 9 months after pyeloplasty for carbohydrate antigen 19-9 assessment, and were correlated with clinical factors. Results: Preoperative carbohydrate antigen 19-9 level was significantly greater in group 1 than in controls. The best cutoff values for serum and urinary carbohydrate antigen 19-9 were 13.21 U/ml and 30.6 U/ml, respectively, with significantly higher sensitivity and specificity for urinary values. Obstruction release was followed by improvement of renal function together with significant reduction in urinary and serum carbohydrate antigen 19-9 at 3 months. Initial pelvis diameter and renographic function significantly correlated with urinary carbohydrate antigen 19-9. No significant correlation was found regarding serum carbohydrate antigen 19-9. Conclusions: Voided urine carbohydrate antigen 19-9 is a noninvasive, clinically applicable marker in congenital obstructive nephropathy. The practical implications of these data for diagnosis and long-term followup in ureteropelvic junction obstruction are significant. Our findings suggest that proper decrease in urinary carbohydrate antigen 19-9 after pyeloplasty is predictive of excellent surgical outcomes and resolution of renal damage.