Table 6.

Measures of agreement between microbiological culture growth results from BALF and NPS specimens with any bacterial load and with bacterial loads meeting the cut-off for infection

	Isolates with any bacterial load			Isolates with a bacterial load meeting the cut-off for infectiona
	S. pneumoniae	H. influenzae	M. catarrhalis	S. pneumoniae	H. influenzae	M. catarrhalis
BALF, n	58	97	94	20	17	12
NPS, n	98	89	106	98	89	106
Both BALF and NPS, n	49	71	83	20	12	11
Sensitivity, value (95% CI)	0.84 (0.73–0.93)	0.73 (0.63–0.82)	0.88 (0.80–0.94)	1.00 (0.83–1.00)	0.71 (0.44–0.90)	0.92 (0.62–1.00)
Specificity, value (95% CI)	0.63 (0.54–0.71)	0.81 (0.71–0.88)	0.76 (0.66–0.84)	0.54 (0.46–0.62)	0.55 (0.48–0.63)	0.47 (0.39–0.54)
PPV, value (95% CI)	0.50 (0.40–0.60)	0.80 (0.70–0.88)	0.78 (0.69–0.86)	0.20 (0.13–0.30)	0.13 (0.07–0.22)	0.10 (0.05–0.18)
NPV, value (95% CI)	0.90 (0.82–0.95)	0.74 (0.65–0.82)	0.87 (0.78–0.93)	1.00 (0.96–1.00)	0.95 (0.89–0.98)	0.99 (0.94–1.00)

BALF, bronchoalveolar lavage fluid; NPS, nasopharyngeal swab; n, number of isolates with positive growth/or meeting the cut-off for infection; CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value

^aBacterial load > 10⁴ CFU/mL if the pathogen was present alone or > 10⁵ CFU/mL if present as co-infection