Table 4. Sensitivity, specifcity and predictive values of renal biometry in the diagnosis of APN.

Volume of larger kidney	Sensitivity ratio	Specifcity ratio	Predictive value (%)
			Positive test	Negative test
>120%	62/70 (89)	76/85 (89)	62/69 (90)	76/85 (89)
>130%	59/70 (84)	82/85 (96)	59/62 (95)	82/93 (88)
>140%	55/70 (79)	85/85 (100)	52/52 (100)	85/102 (83)

Sensitivity = probability of a positive finding in a patient with acute pyelonephritis; Specifcity = probability of a negative finding in a patient without acute pyelonephritis, that is, with acute lower UTI; Predictive value of positive test = percentage of patients with positive test results who have acute pyelonephritis; Predictive value of negative test = percentage of patients with negative test results who have acute lower UTI