The study aimed to evaluate urinary CA 19-9 as a potential biomarker in children with lower urinary tract dysfunction (LUTD) symptoms with a focus on underlying pathology and urodynamic parameters.

This prospective study included a total of 200 children aged between 5 and 16 years, comprising 25 with neurogenic LUTD, 27 with non-neurogenic LUTD, and 148 healthy controls. Urinary CA19-9 was analyzed using ELISA. Urinary CA 19-9 values were compared between groups. CA19-9 levels in the neurogenic group were compared with urodynamic parameters and subgroup analysis according to the presence of upper urinary tract (UUT) damage. In addition, correlation analyses were performed for both the neurogenic and non-neurogenic groups with non-invasive parameters and for the neurogenic group with invasive parameters. ROC analysis was performed to determine the threshold value for the 2 patient groups.

The mean age of the patients was 9.18 years. Urinary CA19-9 levels were found to be 77.34 U/ml in the neurogenic group, 58.63 U/ml in the non-neurogenic group, and 49.87 U/ml in the control group (p<0.001). No statistically significant results were found in the subgroup analysis of the neurogenic group based on UUT damage, a detrusor leak point pressure (DLPP) > 20 cm H₂O, or compliance < 10 ml/cm H₂O. Correlation analysis revealed a significant correlation between urinary CA 19-9 values and PVR only. In ROC analysis for  LUTD children - control comparison, the threshold value of urinary CA 19-9 was 57.46 U/ml. It was 60.53 U/ml for neurogenic and 54.84 U/ml for non-neurogenic group.

Our study demonstrated that urinary CA 19-9 levels were significantly higher in children with LUTD compared both to healthy controls (p < 0.001) and in neurogenic compared to non-neurogenic LUTD (p < 0.001). However, no correlation was found between urinary CA 19-9 levels and urodynamic parameters in the overall LUTD group. Notably, the presence of hydronephrosis (HN) did not affect CA 19-9 levels in children with neurogenic LUTD. Although various biomarkers have been investigated in LUTD, this is the first study to evaluate urinary CA 19-9 with a specific focus on urodynamic parameters.

This prospective study suggests urinary CA 19-9 as a potential biomarker for diagnosing neurogenic and non-neurogenic LUTD in children. However, its correlation with UUT and urodynamic parameters was not established, highlighting the need for larger studies.