Table 5. Associations between selected subject characteristics and discordant QuantiFERON^®-TB Gold In-Tube test and tuberculin skin test results using either a 15 mm or 10 mm cutoff.

	TST ≥ 15 mm but negative QFT-GIT			TST ≥ 10 mm but negative QFT-GIT			TST <15 mm but positive QFT-GIT a
Characteristic	n Concord	n Discord	aOR (95% CI)	n Concord	n Discord	aOR (95% CI)	n Concord	n Discord	OR (95% CI)
Age b	760	18	1.2 (1.0–1.3)	741	37	1.1 (1.0–1.2)	760	9	Not retained
TB prevalence in birth country
<20 cases per 100,000	700	5	1.0	690	15	1.0	700	8	Not retained
20–100 cases per 100,000	19	3	18.0 (3.9–83.8)	17	5	13.5 (4.2–43.6)	19	1
>100 cases per 100,000	41	10	27.8 (8.8–88.0)	34	17	24.2 (10.4–56.4)	41	0
Reactivity to M. avium PPD
No	702	15	Not retained	689	28	1.0	702	8	Not retained
Yes	58	3		52	9	6.2 (2.4–16.1)	58	1

TST = tuberculin skin test; QFT-GIT = QuantiFERON^®-TB Gold In-Tube test; n ^Concord = the number of subjects with concordant TST (at indicated cutoff) and QFT-GIT results; n ^Discord = the number of subjects with discordant TST (at indicated cutoff) and QFT-GIT results; aOR (95% CI) = adjusted Odds Ratios (95% confidence intervals) with boldface font indicating statistically significant differences; TB = tuberculosis.

^a TST induration was 0 mm for all subjects with TST <15 mm but positive QFT-GIT results so that all had TST-negative but QFT-GIT-positive discordance regardless of the TST cutoff used;

^b Increase in odds for each year of age.