Comparing accuracy of urinary biomarkers in differentiation of ureteropelvic junction obstruction from nonobstructive dilatation in children

Comparison of Urinary Biomarkers in Diagnosis of Ureteropelvic Junction Obstruction and Differentiation from Nonobstructive Dilatation

Background and Aims

Differentiation of nonobstructive dilatation (NOD) from ureteropelvic junction obstruction (UPJO) is a challenge in children with antenatally detected hydronephrosis. The aim of this study is to compare the utility of urinary biomarkers: carbohydrate antigen (CA 19-9), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule (KIM) in diagnosing UPJO.

Methods

A prospective study was conducted after obtaining ethical clearance between 2021 and 2022. Group 1 - control group (n = 30): children with normal antenatal ultrasound with no urinary symptoms. Group 2 - study group (n = 48): children with unilateral hydronephrosis: Group 2a - NOD (n = 24): children stable on ultrasound and diuretic renogram and Group 2b - UPJO (n = 24): children who worsened to Grade 4 hydronephrosis on ultrasound/worsening of differential renal function (10% drop) on renogram who underwent pyeloplasty. Urinary biomarkers NGAL, KIM-1, and CA 19-9 were measured using the enzyme-linked immune absorbent assay method.

Results

The urine CA 19-9 level was 128.05 ± 4.08 U/mL in the UPJO group, and this was significantly higher (P = 0.001) than NOD, 70.29 ± 4.41, and controls, 1.91 ± 1.57. The urine NGAL level was 21.41 ± 4.44 pg/mL in UPJO, and this was significantly higher than controls, 2.669 ± 0.513, but not NOD, 24.55 ± 2.67. The urine KIM level was 817 ± 15.84 pg/mL in the UPJO group, and this was significantly higher than controls, 285 ± 8.10, but not NOD, 768.23 ± 15.12. Receiver operating characteristic analysis of CA 19-9 revealed a urine biomarker cutoff of 95 U/mL for diagnosing UPJO (sensitivity 95%; specificity 96%; and area under the curve 0.99).

Conclusions

CA 19-9 is a superior marker compared to NGAL and KIM in differentiating UPJO from NOD. Further studies with larger numbers are warranted.

Role of urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL), Monocyte Chemoattractant Protein-1(MCP-1), and Interleukin-6(IL-6) as biomarkers in pediatric patients with hydronephrosis

OBJECTIVES

The decision to surgically intervene in a hydronephrotic kidney in children is based on many debatable guidelines, some requiring repeated ultrasounds or renal scans. Urinary proteins have the potential to reflect renal disorders and hence can be the alternatives to such scans. Here, we aim to assess the role of urinary Neutrophil Gelatinase-Associated Lipocalin, Monocyte Chemoattractant Protein-1, and Interleukin-6 (IL-6) in such patients.

METHODS

Seventeen children had obstructive hydronephrosis requiring pyeloplasty (UPJO), while seven were kept on conservative management in view of non-obstructive dilation (NOD). Urine samples were measured for the three urinary proteins at the time of presentation and following pyeloplasty using commercially available ELISA kits.

RESULTS

The levels of all three urinary proteins were significantly higher in patients with UPJO children compared to the NOD group. Cut-off values to differentiate obstructive from non-obstructive hydronephrosis were obtained. A significant fall in the post-operative value of urinary IL-6 was also observed.

CONCLUSION

This study highlights the potentiality of urinary proteins as biomarkers in identifying children with hydronephrosis and picking out the ones with obstructive hydronephrosis who will require pyeloplasty. The drop in levels after pyeloplasty can be employed to evaluate the effectiveness of pyeloplasty when sent serially.