Introduction: Obstructive nephropathy, resulting from urinary tract obstruction during fetal development, represents the most common cause of kidney failure in infants and children. Despite an early intrauterine diagnosis through prenatal ultrasound, the determination of the prognosis of the kidney injury’s severity is not well established yet. Therefore, the identification of blood and/or urinary markers to define the progression of renal damage would play an important role in deciding on earlier and more effective therapeutic interventions. Elevated carbohydrate antigen CA19-9 (originally a tumor marker) levels have been described in benign urinary obstruction.

Aim: This study evaluated to which extent this easy-analysis biomarker could help in the earlier diagnosis, especially in doubtful cases, of obstructive uropathies with potential renal damage. We compared it to another biomarker, NGAL, relad to the severity of the obstruction. 

Materials and methods: Forty-six female Wistar rats were divided into five groups, each with different patterns of partial urinary tract obstruction: Control group; OIV group: infravesical obstruction; group OIVd: infravesical obstruction with reversal and relief of the obstruction on the 7th postoperative day; group OUu: right unilateral ureteral obstruction; group OUb: bilateral ureteral obstruction. Baseline determination of CA 19-9, NGAL, and creatinine in urine and blood was performed in the rats prior to surgery (T0). Surgical interventions promoted partial obstruction depending on the group. After 14 days, new measurements (T1) of the markers were taken and compared to baseline values. The OIVd group underwent an intermediate collection after clearance (Ti). 

Results: There was an increase in the urinary concentration of CA19-9 in all obstructed animals. In the OIV, OUb and OIVd groups, the elevation in T1 and Ti, respectively, reached statistical significance in relation to the T0 value. The changes in urinary CA19-9 were more expressive in the groups OIVd (AUC = 0.71), OIV (AUC = 0.81) and OUb (AUC = 0.77). Relief of obstruction in the OIVd group promoted significant reduction in urinary CA 19-9 values in the final evaluation, with AUC = 0.73. There was no positive correlation between the obstructed groups and serum CA 19-9 levels. 

Conclusions: The urinary concentration of CA19-9 increased in the presence of urinary tract obstruction; the performance of urinary CA19-9 as a marker was similar in infravesical (low) and ureteral (high) obstructions, and there was a decline in urinary CA19-9 concentration after clearance.