TABLE 1.

Characteristics of the study population and results of the assays at both time pointsa

Group (no. of subjects)Age, yr (avg ± SD)TSTT-SPOT.TBbQFT-GIT resultc
200520062005200620052006
Induration diam, mm (avg ± SD)ResultInduration diam, mm (avg ± SD)ResultMedian no. of spots (range)ResultMedian no. of spots (range)Result
1 (9)41 ± 130Neg0Neg10 (8-35)Pos1 (0-3)NegNegNeg
2 (1)510Neg0Neg7Pos8PosNegNeg
3 (2)47 ± 180Neg8 ± 0.7Neg13 (12-14)Pos0 (0-0)NegNegNeg
4 (11)42 ± 113 ± 4Neg15 ± 3.4Pos10 (6-60)Pos1 (0-3)NegNegNeg
5 (4)40 ± 139 ± 0Neg18 ± 2.5Pos8 (6-25)Pos15 (12-23)PosNegNeg
6 (1)429Neg19Pos12Pos2NegPos (1.25)Pos (0.58)
7 (1)580Neg19Pos−1Neg0NegPos (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).