TABLE 1.

Correlation^a between microscopic examination and culture results of 500 urine specimens

Gram-stain result	No. (designation) of urine culture results
	Positiveb	Negative	Total
Positivec	119 (a)	3 (b)	122
Negative	5 (c)	373 (d)	378
Total	124	376	500

^aSensitivity [a/(a + c)] = 119/124 (96.0%); specificity [d/(b + d)] = 373/376 (99.2%); positive predictive value [a/(a + b)] = 119/122 (97.6%); negative predictive value [d/(d + c)] = 373/378 (98.7%). 

^bColony counts of >10⁴ to ≥10⁵ CFU/ml. 

^cObservation of ≥2 bacteria per oil immersion field.