Table 2.
Performance of Different Testing and Result Interpretation Strategies.
| CFP-10 or ESAT-6 cut-off | Positive Result | Negative Result | CC % of those tested | False +ve (unnecessary treatment) of non-TB | False -ve (missing treatment) of TB |
|---|---|---|---|---|---|
| Patients with a history of a previous TB disease and newly suspected recurrence of TB (n=44) | |||||
| Blood ELISPOT | 36 (82%) | 8 (18%) | 12 (27%) | 32 (80%) | 0 |
| BAL ELISPOT (Commercial cut-off) | 17 (39%) | 27 (61%) | 31 (70%) | 13 (33%) | 0 |
| >4000 BAL lymphocytes (ELISPOT positive) | 6 (14%) | 38 (86%) | 42 (95%) | 2 (5%) | 0 |
| >4000 BAL lymphocytes (ELISPOT positive) or positive Xpert | 8 (18%) | 36 (82%) | 40 (91%) | 4 (10%) | 0 |
| Xpert alone | 3 (7%) | 41 (93%) | 39 (89%) | 2 (5%) | 3 (75%) |
BAL: bronchoalveolar lavage; CC: correctly classified; NPV: negative predictive value; PPV: positive predicted value; TB: tuberculosis, CFP-10: culture filtrate protein 10, ESAT-6: Early secreted antigenic target 6kDa.