Table 8.
Comparison of detection results for 147 community donors from one community, assayed by IFN-γ ELISPOT assay, T-SPOT.TB assay, and TSTc
| Assay and result | No. (%) of samples with TST resulta |
SFP value (SFC/106 PBMCs or viable cells)b |
||||
|---|---|---|---|---|---|---|
| Positive (≥5 mm) | Negative (0 mm) | Total | P25 | P50 | P75 | |
| IFN-γ ELISPOT assay (total of E6+E7 and E6+E7+C14 assays) | ||||||
| Positive | 35 (23.81) | 9 (6.12) | 44 (29.93) | 169 | 482 | 760 |
| Negative | 87 (59.18) | 16 (10.88) | 103 (70.07) | 0 | 0 | 0 |
| Total | 122 (82.99) | 25 (17.01) | 147 | 0 | 0 | 14 |
| T-SPOT.TB assay (total of panel A and panel B) | ||||||
| Positive | 15 (10.20) | 6 (4.08) | 21 (14.29) | 473 | 152 | 44 |
| Negative | 107 (72.79) | 19 (12.93) | 126 (85.71) | 1 | 3 | 0 |
| Total | 122 (82.99) | 25 (17.01) | 147 | 0 | 1 | 5 |
No individual was found with a TST induration of 1 to 4 mm.
P25, lower quartile SFP value; P50, median SFP value; P75, upper quartile SFP value.
For the T-SPOT.TB assay, a positive detection rate of 14.29% and a median positive SFP value of 152 were found, which were significantly lower than the 29.93% positive detection rate and median positive SFP value of 482 for the combined IFN-γ ELISPOT assay for the same 147 cases (P < 0.05); on the other hand, these positive detection rates were significantly lower than the rate of 82.99% for positive TST results (P < 0.05). Some level of positive detection was achieved by the two IFN-γ ELISPOT assays for both the positive and negative TST detection groups.