TABLE 2.
Serial testing studies of IGRAs in health care workers in countries with low and intermediate incidencesc,d
| Study, yr (reference) | Country | Duration between tests | No. of conversions or reversions/total no. of participants (%) |
||
|---|---|---|---|---|---|
| TST conversions | IGRA conversionsa | IGRA reversionsa | |||
| Slater et al. (87) | USA | 2 yr | 0.4% (historical) | 361/8,227 (4.4) | 613/1,584 (38.7) |
| Dorman et al. 2013 (86) | USA | 6 mo | 21/2,293 (0.9) | For QFT, 138/2,263 (6.1); for T-SPOT, 177/2,137 (8.3) | For QFT, 81/106 (76); for T-SPOT, 91/118 (77) |
| Zwerling et al., 2013 (70) | Canada | 1 yr | 0/241 | 13/245 (5.3) | 8/13 (62) |
| Joshi et al., 2012 (85) | USA | 1 yr | 0.1% (historical) | 71/2,232 (3.2) | 31/69 (45) |
| Park et al., 2012 (84) | South Korea | Once-monthly testing for 1 yr | NA | 25/48 (52) had ≥1 conversion over 1 yr | Not reported |
| Joshi et al., 2012 (73) | USA | 2–30 days | NA | NA | 18/45 (40) |
| Rafiza and Rampal, 2012 (75) | Malaysia | 1 yr | NA | 69/703 (9.8) | 14/59 (23.7) |
| Fong et al., 2012 (71) | USA | 1 yr or 1–6 mo for repeat of positive IGRA | NA | 52/1,857 (2.8) | 8/10 (80)b |
| Torres Costa et al., 2011 (76) | Portugal | 1 yr | 61/199 (30.7); reversion rate = 4/188 (2.1) | 51/462 (11) | 46/208 (22.1) |
| Schablon et al., 2010 (77) | Germany | High-risk HCWs tested annually, all others evaluated every other year | NA | 15/245 (6.1) | 13/42 (32.6) |
| Ringshausen et al., 2010 (78) | Germany | 18 wk | NA | 3/162 (1.9) | 6/18 (33.3) |
| Park et al., 2010 (79) | South Korea | 1 yr | NA | 14/244 (5.7) | NA |
| Lee et al., 2009 (80) | South Korea | 1 yr | 16/75 (21.3) | 21/146 (14.4) | NA |
| Chee et al., 2009 (81) | Singapore | 1 yr | 0/18 (note that the denominator includes only baseline concordant positive results) | 9/182 (4.9) | NA |
| Yoshiyama et al., 2009 (82) | Japan | 2 and 4 yr | NA | 5/277 (1.8) | 13/32 (41) |
| Pollock et al., 2008 (83) | USA | 1–7 mo | NA | 2/43 (4.6) selected HCWs at “increased risk” and negative at baseline | NA |
a
All conversions/reversions, using simple negative/positive results.
b
Note that repeat testing was done among those with positive QFT results close to the cutoff point.
c
HCW, health care worker; IGRA, gamma interferon release assays; NA, data not available; TST, tuberculin skin test.
d
Adapted from reference 90 with permission of the publisher.