Table 4.
Validity of Predictors of Latent Tuberculosis Infection, as Measured by the QuantiFERON Gold In-Tube (QFT), Among US Army Recruits
| Factor | No. (%) of positive RFQ responses (n = 1783) | No. of persons with positive QFT results (n = 36) | RFQ sensitivity, % | RFQ specificity, % | RFQ PPV, % | RFQ NPV, % | RFQ AUC |
| 1. Close contact of TB case | 20 (1.1) | 3 | 8.3 | 99.0 | 15.0 | 98.1 | 0.537 |
| 2. TB prevalence ≥20 cases per 100000 persons in country of birth | 96 (5.4) | 9 | 25.0 | 95.0 | 9.4 | 98.4 | 0.600 |
| 3. Lived with parent born outside of the US | 79 (4.4) | 10 | 27.8 | 96.0 | 12.7 | 98.5 | 0.619 |
| 4. Prior positive TST result | 21 (1.2) | 2 | 5.6 | 98.9 | 9.5 | 98.1 | 0.522 |
| 5. Age ≥30 years | 149 (8.4) | 6 | 16.7 | 91.8 | 4.0 | 98.2 | 0.543 |
| Combinations of factors | |||||||
| 1 or 2 | 113 (6.3) | 12 | 33.3 | 94.2 | 10.6 | 98.6 | 0.638 |
| 1, 2, or 3 | 124 (7.0) | 12 | 33.3 | 93.6 | 9.7 | 98.6 | 0.685 |
| 1, 2, 3, or 4 (selected model) | 166 (9.3) | 16 | 44.4 | 91.4 | 9.6 | 98.8 | 0.684 |
| 1, 2, 3, 4, or 5 | 282 (15.8) | 18 | 50.0 | 84.9 | 6.4 | 98.8 | 0.691 |
| 1, 2, 3, 4, 5, or overseas travel ≥1 month | 318 (17.8) | 18 | 50.0 | 82.8 | 5.7 | 98.8 | 0.697 |
| 1, 2, 3, 4, 5, or residence in congregate setting | 367 (20.6) | 21 | 58.3 | 80.2 | 5.7 | 98.9 | 0.719 |
| Any risk factora | 579 (32.5) | 24 | 66.7 | 68.2 | 4.2 | 99.0 | 0.718 |
NOTE. AUC, area under the curve; NPV, negative predictive value; PPV, positive predictive value; RFQ, risk factor questionnaire; TB, tuberculosis; QFT, Quantiferon® Gold in-tube.
a
Risk factors include all of the previously mentioned risk factors, plus health care work, casual contact with a TB case, and prior TB treatment.