Tuberculin Skin Tests versus Interferon-Gamma Release Assays in Tuberculosis Screening among Immigrant Visa Applicants
Table 3
Subject characteristics associated with chest radiographs consistent with tuberculosis; TST induration 10 mm; or positive QFT-G results.
Characteristic
CXR consistent with tuberculosis
TST induration 10 mm
Positive QFT-G
aOR* (95% CI)
aOR* (95% CI)
aOR* (95% CI)
Total
1,246
272
721
352
Age group
18–20 years
139
9 (6.5%)
1.0
49 (35.3%)
1.0
25 (18.0%)
1.0
21–30 years
293
19 (6.5%)
1.01 (0.44–2.32)
143 (48.8%)
2.17 (1.40–3.35)
77 (26.3%)
1.66 (1.002–2.759)
31–40 years
294
36 (12.2%)
2.06 (0.96–4.42)
199 (67.7%)
4.14 (2.67–6.43)
89 (30.3%)
1.97 (1.19–3.25)
41–50 years
268
80 (29.9%)
5.87 (2.84–12.15)
171 (63.8%)
3.49 (2.24–5.46)
91 (34.0%)
2.29 (1.39–3.79)
51–64 years
207
99 (47.8%)
12.94 (6.23–26.89)
137 (66.2%)
4.22 (2.61–6.81)
60 (29.0%)
1.81 (1.07–3.07)
≥65 years
45
24 (64.4%)
25.12 (10.06–62.70)
22 (48.9%)
1.92 (0.95–3.92)
10 (22.2%)
1.26 (0.55–2.89)
Sex
Female
842
148 (17.6%)
1.0
439 (52.1%)
1.0
226 (26.8%)
Male
404
124 (30.7%)
1.69 (1.24–2.29)
282 (69.8%)
2.09 (1.60–2.73)
126 (31.2%)
N.S. and NIM
BCG status
Not vaccinated
735
191 (26.0%)
398 (54.1%)
1.0
215 (29.3%)
Vaccinated
511
81 (58.8%)
N.S. and NIM
323 (63.2%)
1.62 (1.25–2.09)
137 (26.8%)
Chest exam
Normal
1239
266 (21.5%)
1.0
718 (57.9%)
351 (28.3%)
Abnormal
7
6 (85.7%)
31.23 (3.04–320.68)
3 (42.9%)
N.S. and NIM
1 (14.3%)
N.S. and NIM
M. avium reactivity
No
884
217 (24.5%)
550 (62.2%)
1.0
268 (30.3%)
1.0
Yes
362
55 (15.2%)
N.S. and NIM
171 (47.2%)
0.59 (0.46–0.77)
84 (23.2%)
0.71 (0.53–0.95)
CXR: chest radiographs; TST: tuberculin skin test; QFT-G: QuantiFERON-TB Gold test; : number in subset of ; aOR: adjusted odd ratio; 95% CI: 95% confidence interval; N.S.: not significant; NIM: not in model; BCG: bacille Calette-Guérin; TB: tuberculosis; QFT: QuantiFERON-TB test.
*Multivariate models were created using factors with values ≤0.2 in univariate analysis and <0.05 in stepwise logistic regression until the best fitting, parsimonious model was identified. Model fit was evaluated using the Hosmer-Lemeshow test. Negative and indeterminate QFT-G results were coded as “not positive.” The variable “Prior TB” was not included in the model because all 7 subjects with prior TB had CXR findings consistent with TB disease and its inclusion prevented convergence of the model. Bold font indicates statistically significant adjusted odds ratios (aORs).
