Two of the authors reviewed all of the abstracts and full texts using a review form developed for this purpose. This dynamic decision analytic technique allows the progression from LTBI to active TB and the treatment outcome to be modelled over time.

IGRA tests have replaced or have been added to TST in developed countries, because they appear to be more specific and were considered cost-effective , , , , , , , , , , , , .

2007, 11: 16-26. Because of the different currencies used in the studies, the costs of the TST and IGRA cannot be compared directly. Accordingly, the QFT-only strategy is the most cost-effective for contact investigation in a medium-incidence country like Japan. We conducted a systematic review of all publications that have addressed the cost or cost-effectiveness of IGRAs.

2008, 11: 539-544. ESAT-6 Dheda K, Respirology, 2010 . 2010, 14: 471-481.

However, given the lack of consistency in the critical assumptions (e.g. RD has received reimbursement for attending scientific conferences and/or fees for speaking from Cellestis and Oxford Immunotec. The ultimate aim of LTBI screening is the prevention of progression to active TB via chemoprevention. In general, the higher unit cost of the IGRAs compared to that of the TST is compensated for by cost savings through the more targeted performance of CXRs and offering of chemoprevention. The least costly strategy for immigrants coming from intermediate and high incidence countries versus non screening was CXR screening. Google Scholar. 2005, 80: 675-686. 10.1183/09031936.00145906. Cookies policy. Diel et al.

[21] analysed the cost-effectiveness of five different screening scenarios in contact tracing over a two-year time period in the UK using: 1) TST-only, 2) the T-SPOT.TB-only, 3) positive TST followed by T-SPOT.TB, 4) QFT-IT-only, and 5) positive TST followed by QFT-IT. They compared two versions of QFT and TST-only and accounted for inadequate and indeterminate outcomes of both QFTs, for failure to return for TST reading, and for 2-step TST testing. Google Scholar.

Cost for performing the T-SPOT were assumed to be only ₤ 55.

PubMed  As experience with the IGRAs evolves in routine screening, the IGRAs are endorsed with national recommendations [10–13]. Diel R, Loddenkemper R, Nienhaus A: Evidence based comparison of commercial interferon-gamma release assays for detecting active tuberculosis - a meta-analysis.

volume 11, Article number: 247 (2011)

If sensitivity, specificity and prevalence of LTBI are known in the screened group, the respective formula reads: specificity × (1-prevalence)/specificity × (1-prevalence) + (1-sensitivity) × prevalence. The first one is a cost-effectiveness study among adult close contacts in France. In four of these studies, the two-step strategy and in two the IGRA-only strategy was more cost-effective. There was no stratification with respect to BCG vaccination, and TST specificity was considered to be 80% for all contacts. Lifetime costs and life expectancies for no testing, TST (basically positive at a cut off of ≥ 10 mm) and QFT-IT only and TST/QFT-IT strategies were calculated and compared using incremental cost-effectiveness ratios (ICERs) in euros per life year gained (LYG). [23] used Markov modelling to compare expected TB cases and costs over 20 years following screening for TB with different strategies among hypothetical cohorts of foreign-born immigrants and close contacts in Canada.

The QFT-G [22–24, 26] was used in four studies, one study used QFT-G as well as QFT-IT [25] and three studies used QFT-IT [19, 21, 27]. The NPV of a screening test for latent TB infection is defined as the number of true negative test results divided by the sum of true and false negative results. 10.1183/09031936.06.00011806.

The incremental cost per active TB case prevented, compared with no screening, was ₤ 47,840 in TST, ₤ 39.712 in T-SPOT.TB, ₤ 42,051 in QFT. The ultimate aim of LTBI screening is the prevention of progression to active TB via chemopreventative therapy.

Five studies took only the costs of screening into consideration, while eight studies analysed the cost-effectiveness of different screening strategies.

Eur Respir J.

2010.

Three other studies found the two-step strategy to be less costly [15–17]. This trend is reflected in most national recommendations concerning TB screening (e.g. There, patients were considered positive for LTBI if they had an "abnormal" radiograph and subsequently a positive TST. MMWR Recomm Rep. 2005, 54: 1-141. In the other [22], an age-dependant rate of between 0.0055 (age 20-30) and 0.0018 (age 40-50) per year was used. He has been involved in drafting the manuscript and has given final approval of the version to be published. The total cost of TST screening amounted to ₤ 199,598 per 1,000 contacts compared to T-SPOT.TB at ₤ 203,983, QFT-IT at ₤ 202,921, TST/T-SPOT at ₤ 162,387 and TST/QFT-IT at ₤ 157,048. As with TST, live virus vaccines might affect IGRA test results. Additional studies were identified from the reference list of articles and relevant reviews. Clearly, with the exception of de Perio's work [25], the difference in outcomes of the compared strategies does not result from the sensitivity assumptions made for TST and IGRA by the various authors.

Three different screening strategies were evaluated over a 20-year-period: TST-only, QFT-only and the two-step strategy using the QFT-G to confirm a positive TST. Of these excluded studies, one was published in Japanese, but provided an English abstract. The target population was a hypothetical cohort of 1,000 immunocompetent 20-year-old close contacts to a sputum smear positive index case. On 30 June 2010 with an update on 20 Mai 2011, we conducted a Medline and Embase search of articles published. The ICER of the QFT-G compared with the QFT-IT was US$14.092/QALY for BCG-unvaccinated and US$103.047/QALY for BCG-vaccinated HCWs. Can IGRAs Be Given To Persons Receiving Vaccinations? Diel R, Forßbohm M, Loytved G, Haas W, Hauer B, Maffei D, et al: Recommendations for environmental contact tracing in tuberculosis. Diel R, Loddenkemper R, Nienhaus A: Evidence-based comparison of commercial interferon-gamma release assays for detecting active TB: a metaanalysis. The first study concerning the cost of introducing the IGRAs in screening for LTBI was the paper by Mori and Harada published in 2005 [14]. Cost ratios for the TSTs and IGRAs in different countries were calculated in order to compare the different costs assumed in the studies without having to take into account the particular currencies of the countries. One study used the T-SPOT.TB [28], one study used both IGRAs [21] and all the others used a version of the QFT as IGRA. The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6963/11/247/prepub, University Medical Center Hamburg-Eppendorf, Institute for Health Service Research in Dermatology and Nursing - Hamburg, Germany, Occupational Health Division, S. João Hospital, EPE - Porto, Portugal, Department of Pneumology, Medical School Hannover, Hannover, Germany, You can also search for this author in Pai M, Riley LW, Colford JM: Interferon-gamma assays in the immunodiagnosis of tuberculosis: a systematic review.

2005, 45: 822-823. Observed adherence to chemoprevention in the QFT-positive group was 47%, compared to 12% in the TST-positive group. In all studies the TST-only strategy was the most expensive one (Table 1).

In Europe, this test has long since been replaced by the QuantiFERON-TB Gold In-Tube (QFT-IT). 10.1111/j.1524-4733.2007.00301.x. In contrast to these findings, four other cost-effectiveness studies showed that the two-step strategy with TST and IGRA was the most cost-effective strategy compared to the IGRA-only strategy. Mori T, Harada N: Cost-effectiveness analysis of QuantiFERON-TB 2nd generation used for detection of tuberculosis infection in contact investigations. http://www.biomedcentral.com/1472-6963/11/247/prepub, http://creativecommons.org/licenses/by/2.0, Utilization, expenditure, economics and financing systems. 2008, 177: 1164-1170. The cost of the TST-only strategy was 48.6% higher than the QFT-only strategy (€ 91.06 vs. € 61.29 per close contact).

10.1016/S1473-3099(04)01206-X. This article is published under license to BioMed Central Ltd. In addition, de Perio et al. Like its predecessor, QFT-Plus is an interferon gamma release assay, commonly known as an IGRA, and is a modern alternative to the tuberculin skin test …

Kowada et al.

Albert Nienhaus.

In a further paper, Diel et al. Finally, 15 studies were reviewed as full-text articles and 13 articles met the inclusion criteria (Figure 1). [18] analysed the screening cost for LTBI in 280 immigrants moving from high-incidence countries to Great Britain based on NICE guidelines or when using the IGRAs first. The higher per-test cost of IGRAs may be compensated for by lower post-screening costs (medical attention, chest x-rays and chemoprevention), given the higher specificity of the new tests as compared to that of the conventional TST.

Eur Respir J. Eur Respir J.

10.1007/s00408-009-9182-2. Cost-effectiveness was measured as total costs per active TB case and the ICER per active TB case prevented.

Two studies used the T-SPOT.TB as an IGRA and the other studies used the QuantiFERON-TB Gold and/or Gold In-Tube test. 2010, 137: 952-968. Based purely on financial considerations, it is usually recommended to verify a positive TST with an IGRA and to perform a chest x-ray (CXR) on those who test positive with an IGRA (Nice, DZK and Switzerland).

PubMed 

Oxlade O, Schwartzman K, Menzies D: Interferon-gamma release assays and TB screening in high-income countries: a cost-effectiveness analysis. M. avium) [3]. Diel R, Schaberg T, Loddenkemper R, Welte T, Nienhaus A: Enhanced cost-benefit analysis of strategies for LTBI screening and INH chemoprevention in Germany. Compared to the TST-only strategy, the costs of the IGRA-only strategy were 44% lower.