Table 3 The results of latex agglutination test accompanied with the three culture methods
Culture medium | Level of GBS density (c.f.u. per swab) | No. of samples tested positive (n) | No. of samples positive for GBS (n) | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) |
|---|---|---|---|---|---|---|---|
SBA | High (>100) | 3 | 3 | 100 | 100 | 100 | 100 |
Moderate (50–100) | 4 | 4 | 100 | 100 | 100 | 100 | |
Low (10–50) | 3 | 5 | 60 | 100 | 100 | 71.4 | |
Little (<10) | 0 | 0 | / | / | / | / | |
CNA | High (>100) | 3 | 3 | 100 | 100 | 100 | 100 |
Moderate (50–100) | 5 | 5 | 100 | 100 | 100 | 100 | |
Low (10–50) | 4 | 7 | 57.1 | 100 | 100 | 70 | |
Little (<10) | 0 | 1 | 0 | 100 | 100 | 50 | |
SCB | High (>100) | 15 | 15 | 100 | 100 | 100 | 100 |
Moderate (50–100) | 5 | 5 | 100 | 100 | 100 | 100 | |
Low (10–50) | 0 | 0 | / | / | / | / | |
Little (<10) | 0 | 0 | / | / | / | / |