Table 4. Positive and negative predictive value of urine NAG/urine creatinine ratio.

		Upper urinary tract disease		Total
		Positive	Negative
UNAG/UCr ratio	Positive	56	4	All patients groups except cystitis 60
	Negative	2	38	control 40
	Total	58	42	100

+ve predictive value 93% -ve predictive value 95.0%