TABLE 1.

Criteria for Specific Thresholds for “Abnormal” or (“Positive”) RBUS, Based on Type and Severity of Observed Findings

	Normal ←←←←←←←←←←←←→→→→→→→→→→→→ Abnormal
	No Abnormal Findings Reported	Abnormal Level D (RBUS-D)	Abnormal Level C (RBUS-C)	Abnormal Level Ba (RBUS-B)	Abnormal Level A (RBUS-A)
	N = 1694	N = 41	N = 135	N = 298	N = 91
	75.0%	1.8%	6.0%	13.2%	4.0%
Renal collecting system	Normal	Normal	“Fullness” or “prominence” of collecting system without hydronephrosis	Mild hydronephrosis	>Mild hydronephrosis
			Extra-renal pelvis	Urothelial thickening
Ureter	Normal	Normal	Normal	Mild ureteral dilation	>Mild ureteral dilation
Renal parenchyma	Normal	Duplication Solitary kidney	Simple cyst (single)	Size discrepancy Renal ectopia	Stone(s)
					Dysplasia/increased echogenicity
					Cortical thinning/scar
					Abnormal cortico-medullary differentiation
					Multicystic/polycystic kidney
Bladder	Normal	Normal	Debris Wall thickening	Trabeculation Diverticulum	Ureterocele Dilated posterior urethra

The RBUS severity threshold is set according to column furthest to the right that contains finding(s) observed in the RBUS screening test. The screening test is considered “abnormal” (or “positive”) at the threshold of that column, as well as for all those thresholds to the left of that level.

^aThreshold RBUS-B included findings categorized as “other”: 1 example each of acute pyelonephritis, renal mass, large bladder, urachal remnant, and bilateral enlarged kidneys.