8 376 81.4 0.1 ≤ 0.2 32 71.1 13 28.9 45 9.7 0.2 ≤ 0.35 21 51.2 20 48.8 41 8.9 Neg. 1st QFT 411 89.0 51 11.0 462 100.0 (69.0) 0.35 ≤ 0.5 17 50.0 17 50.0 34 16.3 0.5 ≤ 0.7 10 47.6 11 52.4 21 10.1 0.7–1.0 5 19.2 21 80.8 26 12.5 >1–3 10 18.9 43 81.1 53 25.5 >3–7 2 8.0 23 92.0 25 12.0 >7 2 4.1 47 95.9 49 23.6 Pos. 1st QFT 46 22.1 162 77.9 MAPK inhibitor 208 100.0 (31.0) All 457 68.2 213 31.8 670 100.0 The diameter of the TST was

positively associated with the probability of two consecutive positive QFTs. This probability increased from 10% in those with a TST <10 mm to 31.7% for those with a TST ≥15 mm (Table 3). An increase in the second TST by at least 10 mm was seen in 61 (30.7%) of those who had a first TST <10 mm. Of these 61 HCWs 78.7% were negative in the two consecutive QFTs and 6.6% showed a conversion in QFT (Definition 1). In those HCWs with a TST of 10 ≤ 15 mm who were retested during the study period, four (2.1%) showed decreases in their TST results of ≥10 mm and seven (4.5%) of ≥6 mm. Table 3 Results of first and second QFT in relation to TST and to change in TST TST 1st and 2nd QFT Total −− ++ +− −+ N % N % N % N % N % 0–9 mm 67 74.4 9 10.0 9 10.0 5 5.6 90 13.4 10–14 mm 156 67.8 42 18.3 13 5.7 19 8.3 230 34.3 ≥15 mm 188 53.7 111 31.7 24 6.9 27 7.7 350 52.2 Increase TST*  ≥10 mm 48 78.7 4 6.6 5 8.2 4 6.6 61/199 30.7  ≥6 mm 75 76.5 9 9.2 7 7.1 7 7.1 98/199 49.2 Decrease

TST  ≥10 mm 3 75.0 1 25.0 0 – 0 – 4/188 2.1  ≥6 mm 4 57.1 2 28.6 0 – 1 14.3 7/188 4.5 * First TST <10 mm, second TST ≥10 mm and increase or decrease compared Fosbretabulin concentration to previous TST ≥10 (6) mm % row percent, col % column percent −− both consecutive QFTs were negative −+ first QFT was negative, second Protein kinase N1 QFT was positive, and so on Conversion and reversion rates showed statistically significant differences, depending on the definition used (Table 4). The conversion rates were highest following TST (17.9%) and second highest when crossing the cutoff for QFT

was used as a definition. The 95% CI of these rates does not overlap, indicating a statistically significant difference. Using a gray zone from 0.2 to 0.7 IU/mL and excluding all those who have at least one QFT within this gray zone from calculation resulted in low conversion (3.6%) and reversion rates (5.2%).