Interferon-gamma release assays for the tuberculosis serial testing of health care workers: a systematic review

Ringshausen, Felix C; Schablon, Anja; Nienhaus, Albert

doi:10.1186/1745-6673-7-6

Journal of Occupational Medicine and Toxicology

Table 1 Characteristics and results of studies on serial testing using IGRAs

From: Interferon-gamma release assays for the tuberculosis serial testing of health care workers: a systematic review

Study (Year of publication)	Recruitment period	Country	IGRA(s) used	Time between IGRAs	N*	Initially positive IGRAs^#(%)	IGRA reversions (%)	IGRA conversions (%)
Studies in countries with a high incidence of TB (≥ 100 per 100,000 population and year)
Pai et al. (2006) [17]	2004	India	QFT	18 months	216	38/216 (17.6)	9/38 (23.7)	18/178 (10.1)
Studies in countries with an intermediate incidence of TB (≥ 20 and < 100 per 100,000 population and year)
Chee et al. (2009) [31]	2005–2007	Singapore	T-SPOT	1 year	182	-^†	-^†	9/182 (4.9)
Lee et al. (2009) [32]	2007	South Korea	QFT^‡	1 year	169	23/169 (13.6)	-**	21/146 (14.4)
Yoshiyama et al. (2009) [30]	2003, 2005	Japan	QFT^‡	2–4 years	311	27/311 (8.7)^††	13/31 (41.9)^††	6/287 (2.1)^††
Park et al. (2010) [36]	2008–2009	South Korea	QFT	1 year	275	29/275 (10.5)	-**	14/244 (5.7)
Torres Costa et al. (2011) [40]	2007–2009	Portugal	QFT	1 year	670	208/670 (31.0)	46/208 (22.1)	51/462 (11.0)
Rafiza et al. (2012) [42]	2009–2010	Malaysia	QFT	1 year	769	64/769 (8.3)	19/64 (29.7)	69/704 (9.8)
Studies in countries with a low incidence of TB (< 20 per 100,000 population and year)
Pollock et al. (2008) [29]	2006	USA	QFT^‡	1–7 months	43	-^†	-^†	2/43 (4.7)
Zwerling et al. (2009)^¶[33]	2007–2008	Canada	QFT	1 year	60	4/60 (6.7)	2/4 (50.0)	4/56 (7.1)
Belknap et al. (2010)^¶[34]	Unknown	USA	QFT	6 months	1281	50/1281 (3.9)	20/50 (40.0)	44/1169 (3.8 )
			T-SPOT		68/1281 (5.3)	68/1281 (5.3)	36/68 (52.9)	44/1117 (3.9)
Gandra et al. (2010) [35]^##	2008	USA	QFT	4 weeks	135	-^##	66/135 (48.9)	-^##
Ringshausen et al. (2010) [37]	2005–2008	Germany	QFT	18 weeks	182	18/182 (9.9)	6/18 (33.3)	3/162 (1.9)
Schablon et al. (2010) [38]	2006–2009	Germany	QFT	1 year	287	42/287 (14.6)	13/42 (31.0)	15/245 (6.1)
Schablon et al. (2011) [39]	2008–2009	Germany	QFT	1 year	154	2/154 (1.3)	1/2 (50.0)	1/152 (0.7)
Fong et al. (2012) [41]^§	2007–2010	USA	QFT	1 year	1871	-^§	10/14 (71.4)^§	52/1857 (2.8)

* Number of subjects with IGRA test repeats in the course of the study.
^# Initially positive IGRA results in the cohort with IGRA test repeats.
^† Only subjects with initially negative IGRA results were retested.
^‡ QuantiFERON-TB Gold.
** Reversion rate not reported.
^†† Over the course of the study 139 subjects were retested thrice. Conversion and consecutive reversion occurred in three subjects, while reversion and consecutive conversion occurred in one subject.
^¶ Published abstract.
^## Retrospective chart review. Only subjects with initially positive IGRA results were retested.
^§ Retrospective chart review. According to the institution’s occupational health policy, health care workers with positive IGRA results were not subject to annual repeat testing. Retesting of initially IGRA-positives was performed on an individual basis only. Hence, the remainders of the 486 initially QFT-positive subjects (486/7374; 6.6%) were either advised LTBI therapy, declined retesting, or were lost to follow-up. Of the subjects with IGRA conversions on retesting, ten subjects were retested for a third time, of whom eight (80%) showed a reversion back to a negative IGRA result.
Abbreviations: IGRA = interferon-γ release assay; QFT = QuantiFERON-TB Gold In-Tube; TB = Tuberculosis; T-SPOT = T-SPOT.TB.

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ISSN: 1745-6673

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