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.