Heterogeneity in the protocols and tools (including the uptake of interferon-gamma release assays) employed by different primary care trusts (PCTs) to screen for latent TB infection (LTBI)
| Sequence of tests used | Low TB burden PCT n = 91 (%)* | High TB burden PCT n = 14 (%)* | OR (95% CI) | p Value |
| <16 age group | ||||
| TST+CXR | 23 (25.3) | 5 (35.7) | 1.6 (0.50 to 5.4) | 0.41 |
| TST+CXR+IGRA | 66 (72.5) | 9 (64.3) | 0.68 (0.21 to 2.2) | 0.52 |
| IGRA+CXR | 5 (5.5) | 1 (7.1) | 1.3 (0.14 to 12.2) | 0.81 |
| IGRA used | 66 (72.5) | 9 (64.3) | 0.68 (0.21 to 2.2) | 0.52 |
| Other | 2 (2.2) | 0 (0.0) | NA | 0.57 |
| Low TB burden PCT n = 91 (%)† | High TB burden PCT n = 14 (%) | |||
| 16–35 age group | ||||
| CXR+TST | 9 (9.9) | 0 (0.0) | NA | 0.21 |
| CXR+TST+IGRA | 35 (38.5) | 2 (14.3) | 0.27 (0.06 to 1.3) | 0.09 |
| CXR+IGRA | 3 (3.3) | 0 (0.0) | NA | 0.49 |
| TST+CXR | 14 (15.4) | 6 (42.9) | 4.1 (1.2 to 13.7) | 0.021 |
| TST+CXR+IGRA | 32 (35.2) | 5 (35.7) | 1.0 (0.32 to 3.3) | 0.97 |
| IGRA+CXR | 2 (2.2) | 1 (7.1) | 3.4 (0.29 to 40.5) | 0.33 |
| IGRA used | 68 (74.7) | 8 (57.1) | 0.45 (0.14 to 1.4) | 0.18 |
CXR, chest radiograph; IGRA, interferon-gamma release assay; TST, tuberculin skin test.
<16 age group: 105 PCTs screened for LTBI; 16–35 age group: 105 PCTs screened for LTBI; overall: 107 screened for LTBI.
*Numbers do not add up to total as five low-burden PCTs and one high-burden PCT used more than one method of screening.
†Numbers do not add up to total as four PCTs in low-burden areas used more than one method of screening.