Tuberculin Skin Tests versus Interferon-Gamma Release Assays in Tuberculosis Screening among Immigrant Visa Applicants

Table 5

Subject characteristics associated with TST and QFT-G discordance.

Characteristic	𝑁	TST positive but QFT-G negative		TST negative but QFT-G positive
		𝑛	aOR* (95% CI)	𝑛	aOR* (95% CI)
Total	1,163**	398		74
Age group in years
18–20 yrs	130	27 (20.8%)	1.0	7 (5.4%)	N.S. and NIM
21–30 yrs	270	80 (29.6%)	1.86 (1.12–3.09)	25 (9.3%)
31–40 yrs	279	116 (41.6%)	2.81 (1.72–4.61)	16 (5.7%)
41–50 yrs	252	85 (33.7%)	2.16 (1.30–3.59)	14 (5.7%)
51–64 yrs	189	76 (40.2%)	3.17 (1.86–5.39)	10 (5.3%)
≥65 yrs	43	14 (32.6%)	2.27 (1.03–4.99)	2 (4.7%)
Sex
Female	781	239 (30.6%)	1.0	56 (7.2%)	N.S. and NIM
Male	382	159 (41.6%)	1.62 (1.24–2.10)	18 (4.7%)
BCG status
Not vaccinated	684	203 (29.7%)	1.0	44 (6.4%)	N.S. and NIM
Vaccinated	479	195 (40.7%)	1. 79 (1.38–2.34)	30 (6.3%)

TST: tuberculin skin test; QFT-G: QuantiFERON-TB Gold test; 𝑛: number in subset of 𝑁; aOR: adjusted odd ratio; 95% CI: 95% confidence interval; N.S.: not significant; NIM: not in model; BCG: bacille Calmitte-Guérin; QFT: QuantiFERON-TB test.
*Multivariate models were created using factors with 𝑃 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. Bold font indicates statistically significant aORs.
**Data from 83 subjects with indeterminate QFT-G results were excluded from analysis.