Table 3. Subjects Who Showed Differences in IFN-γ Positivity between the QFT-GIT and ichroma™ IGRA-TB Tests.

Sample	QFT-GIT ELISA		ichroma™ IGRA-TB cartridge
	Result	IFN-γ (IU/mL)	Result	IFN-γ (IU/mL)
1	Positive	0.42	Negative	0.16
2	Positive	0.57	Negative	-0.22
3	Positive	0.95	Negative	0.12

QFT-GIT, QuantiFERON-TB Gold In-Tube; ELISA, enzyme-linked immunosorbent assay; IGRA, IFN-γ release assay; TB, tuberculosis.

The three positive IFN-γ responders on the QFT-GIT test were weakly positive (≥0.35 but <1.0 IU/mL), and those responders did not show positive responses on the test with the ichroma™ IGRA-TB cartridge (≤0.21 IU/mL).