QuantiFERON-TB Gold In-Tube test conversions and reversions among tuberculosis patients and their household contacts in Addis Ababa: a one year follow-up study

Table 2 Levels of IFN-γ at baseline and 12 months later among QFT-GIT negative contacts at baseline

Participant	IFN-γ (IU/ml)	IFN-γ (IU/ml)	QFT-GIT result at 12 months
Participant	at baseline	at 12 months	QFT-GIT result at 12 months
Non-converters
1	0.00	0.05	Negative
2	0.02	0.02	Negative
3	0.12	0.21	Negative
4	0.03	0.03	Negative
5	0.00	0.34	Negative
6	0.00	0.00	Negative
7	0.00	0.04	Negative
8	0.00	0.08	Negative
9	0.00	0.03	Negative
10	0.06	0.17	Negative
11	0.00	0.00	Negative
12	0.01	0.00	Negative
13	0.00	0.03	Negative
Converters
14	0.19	0.53	Positive
15	0.28	0.57	Positive
16	0.21	1.15	Positive
17	0.00	2.19	Positive
18	0.02	2.27	Positive
19	0.03	2.47	Positive
20	0.01	2.68	Positive
21	0.08	4.31	Positive
22	0.02	4.52	Positive
23	0.04	5.54	Positive
24	0.00	8.94	Positive

Contacts from number 1 to 13 (n = 13) were QFT-GIT negative both at baseline and at 12 months with low IFN-γ response whereas contacts from number 14 to 24 (n = 11) were negative at baseline but became positive at 12 months. Nine of the 11 contacts with QFT-GIT test conversions had high IFN-γ response at 12 months whereas 2 (number 14 and 15) of them had IFN-γ values close to the cut-off (0.35).

ISSN: 1471-2334