Table 3.

Predictive values and sensitivity and specificity

Test	Culture positive	Culture negative	Total
Procalcitonin test positive	True positive (a) 4	False positive (b) 29	(a+b) 33
Procalcitonin test negative	False negative (c) 4	True negative (d) 6	(c+d) 10
Total	(a+c) 8	(b+d) 35	43

Sensitivity=50.00%; 95% CI: 16.01-83.99%, Specificity=17.14%, 95% CI: 6.61-33.66%, Positive predictive value=12.12%; 95% CI: 3.48-28.22%, Negative predictive value=60.00%; 95% CI: 26.37-87.60%. CI: Confidence interval