Table 2.

Sensitivity, specificity, positive predictive value and negative predictive value of the method used for ascertaining any of the six types of healthcare-associated infections (HAIs) among 1474 patients enrolled at the University Medical Centre Ljubljana in the Slovenian national HAI prevalence survey in 2011, in comparison to the retrospective medical chart review.

		Retrospective medical chart review
		HAI	No HAI	Total
Slovenian national HAI prevalence survey	HAI	63	16	79
	No HAI	8	1387	1395
	Total	71	1403	1474

Sensitivity: 63/71x100=88.7% (95% CI: 79.0%-95.0%) Specificity: 1387/1403x100=98.9% (95% CI: 98.2%-99.4%) Positive predictive value (PPV): 63/79x100=79.7% (95% CI: 64.9%-84.4%)

Negative predictive value (NPV): 1387/1395x100=99.4% (95% CI: 98.4%-99.5%)