Table 2.
Characteristics of studies for which available data used as reported in the publication
| Author/yr (Reference) | Country/Prevalence | Subjects | Variable Assessed | Type of IGRA | No. of Subjects | Time Points (d) | Study Results Summary |
|---|---|---|---|---|---|---|---|
| Whitworth/2014 (39) | USA/low | Air Force and CDC staff | Automated vs. manual ELISA | QFT | 146 | 0 | 7 (4.8%) Subjects had discordant automated interpretations and 10 (6.9%) in manual interpretations (P = 0.17). |
| Whitworth/2012 (38) | USA/low | Air Force and CDC staff | Variation between 3 laboratories | QFT | 91 | 0 | 7 (7.7%) Subjects were discordant; 6 of them had QFT responses within 0.25 IU/ml of the cut-off. |
| Sauzullo/2011 (43) | Italy/low | Health-care workers | Boosting by skin test | QFT | 69 | 0, 7, 14, 28, 42 | Conversion in 1 subject in Day 14 with subsequent reversion. |
| Powell/2011 (28) | USA/low | Volunteers | Repeat over time | QFT | 864 | 0, 14– 84 | Study did report change of QFT results only for unusual IFN-γ measurements and did not assess change of IGRA in repeated testing. |
| Whitworth/2012 (27)* | USA/low | Air Force and CDC staff | Incubation delay (<1 h vs.11–12 h) | QFT | 149 | 0 | Discordant rates of 6.8%. Significantly lower QFT responses with longer incubation delays (P = 0.001) |
| Incubation time (23–24 vs.16–17 h) | QFT | 152 | 0 | Discordant rates of 5.3%. Significantly lower QFT responses were seen with shorter incubation times (P = 0.002). | |||
| Incubation temperature (35°C vs. 37°C) | QFT | 102 | 0 | Discordant rates of 7.8%. | |||
| Same conditions | QFT | 145 | 0 | Discordant rates of 4.8%. | |||
| Mazurek/2012 (29)* | USA/low | Unclear | Blood collection time: a.m. vs. p.m. | QFT | 146 | 0 | Discordance in 8.9% of subjects. |
| Repeat over time | QFT | 149 | 0, 6 | Discordance in 6% of subjects. | |||
| Ringshausen/2011 (22)† | Germany/low | Health-care workers | Same conditions | QFT | 35 | 0 | There were no conversions or reversions. |
| Repeated reading (0, 5, 15, 30, 60 min) | QFT | 35 | 0 | There were no conversions or reversions. |
Definition of abbreviations: IGRA = IFN-γ release assay; QFT = QuantiFERON-TB Gold In-Tube.
*
Study published as abstract or conference presentation.
†
Quantitative data only available for a part of this study.