Table 5.

Quantitative results of TST, C-TST and IGRA in skin testing converted subjects.

TST conversion*(N = 50)	Baseline IGRA+ (N = 23) median (IQR)			Baseline IGRA- (N = 27) median (IQR)
	Baseline	3-month follow-up	p	Baseline	3-month follow-up	p
TST induration, mm	0.00 (0.00–0.00)	13.50 (11.00–20.00)	< 0.001	0.00 (0.00–0.00)	13.50 (11.50–16.00)	< 0.001
IGRA TB1-Nil, IU/ml	0.85 (0.49–1.44)	1.33 (0.43–3.70)	0.020	0.01 (0.00–0.08)	0.01 (0.00–0.20)	0.024
IGRA TB2-Nil, IU/ml	0.81 (0.51–1.46)	1.43 (0.73–3.49)	0.017	0.02 (0.00–0.08)	0.03 (0.00–0.22)	0.004
C-TST conversion& (N = 26)	Baseline IGRA+ (N = 17) median (IQR)			Baseline IGRA– (N = 9) median (IQR)
	Baseline	3–month follow–up	p	Baseline	3–month follow–up	p
C-TST induration/ erythema, mm	0.00 (0.00–0.00)	20.00 (17.50–23.00)	< 0.001	0.00 (0.00–0.00)	18.00 (10.00–24.00)	0.004
IGRA TB1-Nil, IU/ml	0.68 (0.49–2.01)	1.45 (0.97–2.51)	0.132	0.04 (0.01–0.09)	0.43 (0.08–0.76)	0.016
IGRA TB2-Nil, IU/ml	0.72 (0.55–1.78)	1.45 (0.86–2.28)	0.109	0.02 (0.01–0.08)	0.62 (0.06–0.72)	0.016

C-TST, Creation tuberculin skin test; IGRA, Interferon-gamma release assay; IQR, Interquartile range; TST, Tuberculin skin test; The differences were tested by Wilcoxon matched-pairs signed-rank test.

^*TST conversion was defined as the average diameter of induration ≥10 mm for those with baseline survey < 5 mm, or increased ≥ 10 mm when the baseline survey result was between 5 and 10 mm.

^&C-TST conversion was defined as the average diameter of induration and erythema increased from < 5mm at baseline survey to induration or erythema ≥ 5mm at follow-up survey.