TABLE 2.

Mean analytical data showing TS-TB performancea

AssayNo. of SFCc representing the indicated IFN-γ test result
Positiveb (n = 7)Negatived (n = 57)Indeterminatee (n = 10)
Control7 ± 8 [4]4 ± 4 [2]17 ± 19 [8]
ESAT-634 ± 57 [7]4 ± 5 [3]16 ± 23 [8]
CFP-1031 ± 50 [11]3 ± 4 [1]18 ± 22 [11]
PHAf145 ± 100 [158]92 ± 84 [52]36 ± 39 [18]
  • a Data are expressed as means ± standard deviations [median]. n, number of patients.

  • b A result showing a total of 0 to 5 spots was designated a positive result for the control; a result showing ≥6 spots was designated a positive result for TB antigen-stimulated samples. A result showing a total of 6 to 10 spots was designated a positive result for the control; a result showing at least twice the number of spots seen with the control was designated a positive result for TB antigen-stimulated samples. A result showing a total of 11 to 20 spots was designated a positive result for the control; a result showing at least triple the number of spots seen with the control was designated a positive result for TB antigen-stimulated samples.

  • c SFCs, spot-forming cells.

  • d Results for which the positive criteria not met were designated negative results.

  • e Results showing that the TB antigen-stimulated samples and positive control were not responsive were designated indeterminate results.

  • f PHA, phytohemagglutinin.