Positivity to TST and IGRA test and LTBI estimation
| A | B | C | D | E | F | |
| Total# N | TST-positive n (% A) | TST-positive at second-level screening¶ n (% B) | IGRA-positive n (% C) | Estimated LTBI cases+ n (% A) | Literature estimates for LTBI prevalence§ % | |
| Total | 5255 | 2259 (43.0) | 1302 (57.6) | 844 (64.8) | 1464 (27.9) | - |
| Geographical region and country of origin | ||||||
| West Africa | 2380 | 1153 (48.4) | 741 (64.3) | 480 (64.8) | 747 (31.4) | 19 |
| Guinea | 327 | 178 (54.4) | 90 (50.6) | 62 (68.9) | 123 (37.6) | 22 |
| Nigeria | 562 | 217 (38.6) | 149 (68.7) | 100 (67.1) | 146 (26.0) | 18 |
| East Africa | 1124 | 448 (39.9) | 212 (47.3) | 176 (83.0) | 372 (33.1) | 22 |
| Eritrea | 572 | 182 (31.8) | 62 (34.1) | 49 (79.0) | 144 (25.2) | 7 |
| Somalia | 454 | 221 (48.7) | 126 (57.0) | 110 (87.3) | 193 (42.5) | 22 |
| Asia | 1213 | 465 (38.3) | 291 (62.6) | 141 (48.5) | 225 (18.6) | 27 |
| Bangladesh | 384 | 192 (50.0) | 124 (64.6) | 48 (38.7) | 74 (19.3) | 28 |
| Pakistan | 383 | 156 (40.7) | 90 (57.7) | 54 (60.0) | 94 (24.5) | 29 |
| Other | 408 | 133 (32.6) | 58 (43.6) | 47 (81.0) | 108 (26.5) | - |
| Unknown | 130 | 68 (52.3) | - | - | - | - |
| WHO region of origin | ||||||
| WHO AFR | 3697 | 1688 (45.7) | 997 (59.1) | 693 (69.5) | 1173 (31.7) | 22 |
| WHO EMR | 987 | 294 (29.8) | 166 (56.5) | 97 (58.4) | 172 (17.4) | 16 |
| Other | 441 | 217 (49.2) | 139 (64.1) | 54 (38.8) | 84 (19.0) | - |
| Unknown | 130 | 68 (52.3) | - | - | - | - |
Missing data for one or more variables are collected as “unknown”, except for missing result for TST. TST: tuberculin skin test; IGRA: interferon-γ release assay; LTBI: latent tuberculosis infection; WHO: World Health Organization; WHO AFR: WHO African Region; WHO EMR: WHO Eastern Mediterranean Region. #: the total number of individuals (A) was calculated as the total number of subjects who underwent TST minus those with active TB; ¶: second-level screening included both chest radiography and IGRA testing, performed at the Villa Marelli Institute; +: the estimated prevalence of LTBI (E) was calculated using the % of IGRA-positive people among the TST-positive people who underwent further testing with IGRA at the Villa Marelli Institute (D/C) applied to the number of those lost between TST and IGRA evaluations (×(B−C)), and assuming they had the same level of positivity as those tested with IGRA. This figure was then added to those with a positive IGRA test (D) to derive the numerator; §: literature estimates are taken from Houben and Dodd [29].