Table 3—

Correlation between tuberculin reaction size and the net-spot counts in T-Spot.TB test among the whole cohort before and after stratification by age and smoking

Group	Subjects n	ESAT6 well		CFP10 well
Group	Subjects n	Correlation^#	p-value	Correlation^#	p-value
Whole cohort	134	0.336	<0.001	0.243	<0.01
Age <65 yrs	91	0.324	<0.01	0.253	0.02
Age ≥65 yrs	43	0.422	<0.01	0.197	0.21
Current smokers	32	0.030	0.87	-0.096	0.60
Never- or ex-smokers	102	0.375	<0.001	0.308	<0.001

ESAT: early secretary antigenic target; CFP: culture filtrate protein. ^#: Spearman’s rank correlation coefficients between the tuberculin reaction size and the net spot count (test well count−negative control well count) of T-Spot.TB test.