Objective. To study the variability of assessing the vesicoureteral reflux (VUR) grade on voiding cystourethrogram.

Materials and methods. As part of a prospective study, 126 digital images of voiding cystourethrogram of patients with primary vesicoureteral reflux were selected from the clinical database. All the images were interpreted independently by two urologists and two radiologists according to the grading system of the International Reflux Study in Children working at our institution. The images were re-rated by the same doctors in 7—10 days. The consistency of the primary image ratings of all study participants with each other as well as each expert’s primary and repeated assessments was examined. The percentage of agreement and the kappa statistics were used as the variability indices.

Results. All four experts agreed on the VUR grade in 59.5% of ureters. The intrarater reliability was high and ranged from 96.4 to 97.6%, the kappa value was from 0.95 to 0.97. The interrater agreement was substantial. The pediatric radiologists had interrater reliability 81.7%, kappa 0.76; the urologists — 79.8% and 0.73, respectively. The agreement between radiologists’ and urologists’ assessments was on a substantial level as well, the variability absence was noted in 73.4—78.6%, the kappa value ranged from 0.65 to 0.71.

Conclusion. Agreement of the vesicoureteral reflux grade assessments by experts working at the same institution is at an acceptable level. However, the existing variability in the interpretation may be important for choosing the treatment method and assessing its effectiveness.