TABLE 1.
Characteristics of the study population and results of the assays at both time pointsa
| Group (no. of subjects) | Age, yr (avg ± SD) | TST
|
T-SPOT.TBb
|
QFT-GIT resultc
|
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2005
|
2006
|
2005
|
2006
|
2005 | 2006 | ||||||
| Induration diam, mm (avg ± SD) | Result | Induration diam, mm (avg ± SD) | Result | Median no. of spots (range) | Result | Median no. of spots (range) | Result | ||||
| 1 (9) | 41 ± 13 | 0 | Neg | 0 | Neg | 10 (8-35) | Pos | 1 (0-3) | Neg | Neg | Neg |
| 2 (1) | 51 | 0 | Neg | 0 | Neg | 7 | Pos | 8 | Pos | Neg | Neg |
| 3 (2) | 47 ± 18 | 0 | Neg | 8 ± 0.7 | Neg | 13 (12-14) | Pos | 0 (0-0) | Neg | Neg | Neg |
| 4 (11) | 42 ± 11 | 3 ± 4 | Neg | 15 ± 3.4 | Pos | 10 (6-60) | Pos | 1 (0-3) | Neg | Neg | Neg |
| 5 (4) | 40 ± 13 | 9 ± 0 | Neg | 18 ± 2.5 | Pos | 8 (6-25) | Pos | 15 (12-23) | Pos | Neg | Neg |
| 6 (1) | 42 | 9 | Neg | 19 | Pos | 12 | Pos | 2 | Neg | Pos (1.25) | Pos (0.58) |
| 7 (1) | 58 | 0 | Neg | 19 | Pos | −1 | Neg | 0 | Neg | Pos (0.56) | Neg |
a
Pos, positive; Neg, negative.
b
The cutoff point for the T-SPOT.TB assay is six spots above nil (spots obtained in the medium-stimulated well).
c
The values in parentheses are given as IU/ml. The cutoff point for the QFT-GIT assay is 0.35 IU/ml above nil (IU/ml IFN-γ produced in the unstimulated tube).