| | cut-off 0.400 | cut-off 0.200 |
|---|
| | PCR posb | PCR negb |
TOTAL
a
| PCR posb | PCR negb |
TOTAL
a
|
|---|
TB pos (n) | 199 | 41 |
240
| 221 | 19 |
240
|
TB neg (n) | 21 | 2739 |
2760
| 414 | 2346 |
2760
|
TOTAL (n)
|
220
|
2780
|
3000
|
635
|
2365
|
3000
|
PPVc (%) | 90.4 | 34.8 |
NPVc (%) | 98.5 | 99.1 |
- a Based on the assumption of a mean rate of 8.0% true TB positive specimens and a total number of 3000 specimens in a routine TB laboratory per year, the resulting numbers of TB positive and negative samples were calculated.
- b Based on the specificity and sensitivity values found in this study, the numbers of expected PCR positive and negative results among 3000 were calculated. Resulting numerical values were rounded.
- c Positive and negative predictive values were deduced from calculated PCR positive and negative results.
