Table 4.
Sensitivities and specificities of multiplex real-time PCR for detection of S. pneumoniae and H. influenzae.
| Species | Reference test | Detection limit of the assay | Cutoff 105 copies/mL | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Sensitivity | Specificity | PPVa | NPVb | Sensitivity | Specificity | PPV | NPV | ||
| S. pneumoniae | BAL culture, blood culture and urinary antigen test | 95% (20/21) |
75% (101/135) |
37% (20/54) |
99% (101/102) |
90% (19/21) |
80% (108/135) |
41% (19/46) |
98% (108/110) |
| BAL culture, blood culture and urinary antigen tes + lytA PCR | 91% (43/47) |
89% (97/109) |
78% (43/55) |
96% (97/101) |
79% (37/47) |
95% (104/109) |
88% (37/42) |
91% (104/114) |
|
| H. influenzae | BAL culturec | 90% (28/31) |
65% (81/125) |
39% (28/72) |
96% (81/84) |
81% (25/31) |
85% (106/125) |
57% (25/44) |
95% (106/112) |
| BAL culturec + fucK PCRd | 93% (69/74) |
96% (79/82) |
96% (69/72) |
94% (79/84) |
63% (47/74) |
100.0% (82/82) |
100% (47/47) |
75% (82/109) |
|
a Positive predictive value
b Negative predictive value
c Blood culture were also performed for H. influenzae but all were negative
d fucK PCR was performed in the PCR positive and culture negative samples
Analysis of bronchoalveolar lavage from 156 adults with lower respiratory tract infection.