Table 1.
Characteristics of studies for which additional data were obtained from the authors
| Author/yr (Reference) | Country/Prevalence | Participants | Variable Assessed | Type of IGRA | No. of Subjects | Time Points (d) |
|---|---|---|---|---|---|---|
| Slater/2013 (31) | USA/low | Health-care workers | Repeat over time; only positive results repeated* | QFT | 537 | 0, 1–30 |
| Joshi/2012 (5) | USA/low | Health-care workers | Repeat over time; only positive results repeated* | QFT | 45 | 0, 2–30 |
| Ringshausen/2011 (22)† | Germany/low | Health-care workers | Repeat over time | QFT | 35 | 0, 7, 14, 21, 28 |
| T-SPOT | 35 | 0, 7, 14, 21, 28 | ||||
| Gandra/2010 (4) | USA/low | Health-care workers | Repeat over time; only positive results repeated* | QFT | 135 | 0, within 28 d |
| Ritz/2011 (41) | Australia/low | Students | Boosting by skin test | QFT | 15 | 0, 42, 70 |
| Baker/2009 (40) | USA/low | Immigrants | Boosting by skin test | QFT | 60 | 0, 14–185 |
| Cummings/2009 (44) | USA/low | Health-care workers | Boosting by skin test | QFT | 64 | 0, 9 |
| Leyten/2007 (42) | Netherlands/low | Volunteers | Boosting by skin test | QFT | 14 | 0, 3 |
| Doberne/2011 (32) | USA/low | Volunteers | Preanalytical delay (0, 6,12 h) | QFT | 128 (6 h), 127 (8 h) | 0 |
| Herrera/2010 (33) | USA/low | Volunteers/health-care workers | Preanalytical delay (0, 6, 12 h) | QFT | 20 (6 h), 41 (12 h) | 0 |
| Metcalfe/2013 (23) | USA/low | Petrochemical workers | Same conditions | QFT | 363 | 0 |
| Scott/2010 (26)‡ | South Africa/high | Students/health-care workers | Same conditions | QFT | 19 | 0 |
| Shanaube/2010 (37) | Zambia/high | Volunteers | Effect of storage temperature 37°C vs. < 25°C | QFT | 14 | 0 |
| Hang/2009 (35) | Viet Nam/high | Volunteers | Between-operators variability | QFT | 23 | 0 |
| Min/2013 (36) | South Korea/medium | Volunteers | Incubation time (24, 48, 72 h) | QFT | 33 | 0 |
| Dorman/2014 (6) | USA/low | Health-care workers | Repeat over time | QFT | 137 | 0, 5–21 |
| T-SPOT | 122 | 0, 5–21 | ||||
| Same conditions | QFT | 139 | 0 | |||
| T-SPOT | 125 | 0 | ||||
| Boosting by skin test | QFT | 66 | 0, 7–21 | |||
| T-SPOT | 63 | 0, 7–21 | ||||
| ELISA rerun | QFT | 245 | 0, 8 (0–10) | |||
| Gaur/2013 (34) | USA/low | Volunteers | Incubation time (16, 20, 24 h) | QFT | 50 | 0 |
| Blood volume (0.8, 1.0, 1.2 ml) | QFT | 50 | 0 | |||
| Shaking (gentle vs. vigorous) | QFT | 40 | 0 | |||
| van Zyl-Smit/2009 (30) | South Africa/high | Health-care workers | Repeated reading (0, 2.5, 5, 30, 60, 90, 120 min) | QFT | 19 | 0 |
| Repeat over time | QFT | 14 | 0, 7, 14 | |||
| T-SPOT | 14 | 0, 7, 14 | ||||
| Detjen/2009 (24) | South Africa/high | Health-care workers | Repeat over time | QFT | 15 | 0, 3 |
| Same conditions (6 duplicates) | QFT | 27 | 0 | |||
| Plasma storage | QFT | 21 | 0 | |||
| Fresh vs. 4°C vs. −80°C | ||||||
| Between-operator variability | QFT | 19 | 0 | |||
| Veerapathran/2008 (25) | India/high | Health-care workers | Repeat over time | QFT | 14 | 0, 3, 9, 12 |
| Same conditions (4 duplicates) | QFT | 14 | 0 |
Definition of abbreviations: IGRA = IFN-γ release assay; QFT = QuantiFERON-TB Gold In-Tube, T-SPOT = T-SPOT.TB.
*
Subjects with indeterminate results removed.
†
Quantitative data only available for a part of this study.
‡
Study published as abstract or conference presentation.