Renal tubular markers as screening tools for severe vesicoureteral reflux
Severe (grades IV and V) vesicoureteral reflux (VUR) is a risk factor for acute pyelonephritis, renal scars, and renal failure. This study evaluates albumin and N-acetylglucosaminidase (NAG) urinary excretion, and renal concentrating ability as screening tools to select patients for voiding cystourethrogram (VCUG). Children (111 M, 52 F) aged 10.97 ± 21.17 months (mean + SD), diagnosed with UTI, and who had undergone renal ultrasound and a VCUG, underwent a desmopressin test and had albumin/creatinine and NAG/creatinine urinary excretion measured. Urine osmolality was significantly lower in 27 children with severe VUR (375.3 ± 171.8 mOsm/kg; mean + SD) compared to 100 patients with normal VCUG (611.5 ± 175.8 mOsm/kg), p < 0.001, and to 36 patients with VUR grades I to III (636.2 ± 180.2 mOsm/kg), p < 0.001. NAG/creatinine ratio was significantly elevated in 20 children with severe VUR (26.4 (28.3) U/g); median and interquartile range compared to 67 children with normal VCUG (10.8 (17.9) U/g), p = 0.003, and to 20 patients with VUR grades I to III (7.6 (21.1) U/g), p = 0.009.
What is Known:
• Severe vesicoureteral reflux (SVUR) may contribute to renal damage. Severe vesicoureteral reflux is diagnosed by voiding cystourethrogram and represents about 10% of all patients with VUR. Currently, there are no reliable tests used prior to VCUG to help on the decision of obtaining a VCUG to diagnose SVUR.
What is New:
• This study shows that renal tubular markers (concentrating ability and N-acetylglucosaminidase (NAG) excretion) are useful tests prior to voiding cystourethrogram to screen for severe vesicoureteral reflux.
• This study suggests the use of renal concentrating ability and urinary N-acetylglucosaminidase (NAG) excretion to screen for severe vesicoureteral reflux before requesting a voiding cystourethrogram.
KeywordsN-Acetylglucosaminidase Urinary concentrating capacity Urine albumin Vesicoureteral reflux Voiding cystourethrogram
Negative predictive value
Positive predictive value
Urinary tract infection
All authors contributed equally to this study and manuscript. All authors contributed to the final version of this manuscript.
Victor Garcia Nieto was involved in designing the study, writing the manuscript, and performing the statistical analysis.
Victoria E. Garcia-Rodriguez participated in designing the study and doing the statistical analysis.
Maria Isabel Luis-Yanez, Margarita Monge, and Pedro Arango-Sancho collected the data.
Eduardo H. Garin participated in designing the study and writing the manuscript.
Compliance with ethical standards
The performed study is in accordance with the ethical standards and with the 1964 Helsinki declaration.
Conflict of interest
The authors declare that they have no conflict of interest.
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