Table 3.
Results of IGRAs in 25 cases with discordant results between QFT-GIT/QFT-Plus and TB-Feron tests.
| Previous IGRA | Initial IGRA after Enrollment | Repeat IGRA during Follow Up | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | Group | QFT-GIT/QFT-Plus | QFT-Plus | TB-Feron | QFT-Plus | TB-Feron | ||||||||
| TB1 | TB2 | Result | TB1 | TB2 | Result | TBF | Result | TB1 | TB2 | Result | TBF | Result | ||
| 1 | ATB | 0.36 | 6.21 | Positive | 0.10 | Negative | ||||||||
| 2 | ATB | 0.35 | 0.97 | Positive | 0.08 | Negative | ||||||||
| 3 | ATB | 0.15 | 0.30 | Negative | 0.49 | Positive | ||||||||
| 4 | P-LTBI | 1.17 | − | Positive | 0.2 | 0.26 | Negative | 0.48 | Positive | |||||
| 5 | P-LTBI | 0.64 | − | Positive | 0.08 | 0.11 | Negative | 1.30 | Positive | |||||
| 6 | P-LTBI | 0.37 | − | Positive | 0.19 | 0.20 | Negative | 0.56 | Positive | 0.11 | 0.23 | Negative | 1.05 | Positive |
| 7 | P-LTBI | 0.49 | 0.66 | Positive | 0.16 | 0.06 | Negative | 0.38 | Positive | |||||
| 8 | P-LTBI | 0.26 | 0.40 | Positive | 0.06 | 0.08 | Negative | 0.43 | Positive | |||||
| 9 | P-LTBI | 0.37 | − | Positive | 0.02 | 0.03 | Negative | 0.05 | Indeterminate † | |||||
| 10 | P-LTBI | 1.51 | − | Positive | 0.03 | 0.0 | Negative | 0.11 | Indeterminate † | |||||
| 11 | P-LTBI | 1.79 | − | Positive | 0.01 | 0.0 | Negative | 0.07 | Negative | |||||
| 12 | P-LTBI | 0.53 | 0.62 | Positive | 0.01 | 0.01 | Negative | 0.04 | Negative | |||||
| 13 | P-LTBI | 0.35 | 0.33 | Positive | 0.01 | 0.04 | Negative | 0.20 | Negative | |||||
| 14 | P-LTBI | 0.49 | 0.60 | Positive | 0.08 | 0.07 | Negative | 0.07 | Negative | |||||
| 15 | P-LTBI | 1.28 | 1.01 | Positive | 0.0 | 0.0 | Negative | 0.0 | Negative | |||||
| 16 | H-LTBI | >10 | − | Positive | 0.35 | 0.43 | Positive | 0.28 | Negative | |||||
| 17 | H-LTBI | 0.29 | 0.65 | Positive | 0.19 | 0.69 | Positive | 0.0 | Negative | 0.09 | 0.93 | Positive | 0.06 | Negative |
| 18 | H-LTBI | 0.42 | − | Positive | 0.14 | 0.18 | Negative | 0.43 | Positive | 0.06 | 0.13 | Negative | 0.48 | Positive |
| 19 | HC | 0.15 | 0.06 | Negative | 0.57 | Positive | 0.03 | 0.06 | Negative | 0.47 | Positive | |||
| 20 | HC | 0.05 | 0.12 | Negative | 0.69 | Positive | ||||||||
| 21 | HC | 0.002 | 0.13 | Negative | 0.82 | Positive | ||||||||
| 22 | HC | 0.02 | 0.0 | Negative | >10 | Positive | ||||||||
| 23 | HC | 0.00 | − | Negative | 0.02 | 0.0 | Negative | 0.48 | Positive | 0.01 | 0.01 | Negative | 0.05 | Negative |
| 24 | HC | 0.15 | − | Negative | 0.0 | 0.34 | Negative | 1.11 | Positive | 0.20 | 0.0 | Negative | 0.01 | Negative |
| 25 | HC | 0.34 | 0.32 | Negative | 0.2 | 0.17 | Negative | 1.72 | Positive | 0.0 | 0.0 | Negative | 0.01 | Negative |
Previously performed QFT-GIT or QFT-Plus assays are presented as previous IGRA, and the QFT-Plus and TBF performed after enrollment were considered as initial and repeated QFT-Plus or TBF. † Indeterminate result due to mitogen minus nil <0.5. Absence of an IFN- value in the TB2 column for “Previous IGRA” presents the results from the QFT-GIT test. Abbreviations: IGRA, interferon-gamma-release assay; TB, tuberculosis; TB1, QFT-Plus TB1 tube; TB2, QFT-Plus TB2 tube; TBF, TB-Feron antigen tube; IFN-, interferon-gamma.