Age, BCG vaccination status and clinical risk factors by LTBI screening results
| TST (n=1529) | QFT (n=685) | TSPOT (n=844) | ||||
|---|---|---|---|---|---|---|
| Parameter | Positive (n=173) | Negative (n=1356) | Positive (n=50) | Negative (n=635) | Positive (n=70) | Negative (n=774) |
| Age, mean years (±SD) | 52.0±12.1 | 51.6±14.1 | 58.4±12.7 | 51.1±13.9 | 59.5±12.9 | 50.8±13.8 |
| BCG,* n (%) | 50 (28.9) | 154 (11.4) | 5 (10.0) | 127 (20.0) | 9 (12.9) | 63 (8.1) |
| Prior TB,† n (%) | 16 (9.2) | 18 (1.3) | 7 (14.0) | 13 (2.0) | 8 (11.4) | 6 (0.8) |
| Contact,† n (%) | 29 (16.8) | 52 (3.8) | 3 (6.0) | 30 (4.7) | 11 (15.7) | 37 (4.8) |
| CXR,‡ n (%) | 15 (8.7) | 12 (0.9) | 3 (6.0) | 7 (1.1) | 15 (21.4) | 2 (0.3) |
| CRF,† n (%) | 48 (27.7) | 74 (5.5) | 9 (18.0) | 45 (7.1) | 24 (34.3) | 44 (5.7) |
Data represent patient numbers (%) positive for vaccination or stated risk factor unless otherwise indicated.
CRF was defined as the presence of at least one of the following three clinical risk factors: history of prior TB, close contact and chest x-ray suggestive of LTBI (CXR).
↵* Twenty-one patients had missing data on BCG vaccination (2 in the TST-positive group and 19 in the TST-negative group). Eighteen of the 21 patients were tested with QFT (1 positive, 17 negative) and the remaining 3 were tested with TSPOT (1 positive, 2 negative).
↵† Five patients had missing results on prior TB/contact and therefore also on CRF. All 5 were in the TST-negative group (2 in the QFT-negative group, 2 in the TSPOT-positive group and 1 in the TSPOT-negative group).
‡ Chest x-ray was performed in 88.2–97.1% of patients in each group.
BCG, Bacille Calmette-Guérin; CRF, compound risk factor; LTBI, latent tuberculosis infection; QFT, Quantiferon TB Gold; TSPOT, TSPOT.TB; TST, tuberculin skin test.