TB Gold Test Research Articles

Clinical utility of the quantiferon TB-Gold (in-tube method) test in the diagnosis of tuberculosis in children

Clinical utility of the quantiferon TB-Gold (in-tube method) test in the diagnosis of tuberculosis in children

Clinical experience of QuantiFERON®-TB Gold testing in patients with psoriasis treated with tumour necrosis factor blockers in Taiwan

In Taiwan, an intermediate tuberculosis burden country, around 9·3% of patients with rheumatoid arthritis treated with adalimumab develop tuberculosis despite prescreening with the tuberculin skin test. Within the Asia-Pacific region, the tuberculosis risk in patients with psoriasis who use tumour necrosis factor (TNF) blockers is unknown. This study reports the use of QuantiFERON(®) -TB Gold (QFT-G) (Cellestis, Melbourne, Vic., Australia) as a screening method for latent tuberculosis infection (LTBI) in patients with psoriasis. This retrospective review evaluated 216 patients with psoriasis in whom TNF blockers were considered between 2004 and 2009 in a tertiary referral hospital in Taiwan. Beginning in 2007, QFT-G was performed on all patients who were candidates for TNF blockers. Seventeen patients who used TNF blockers for less than 4 weeks were excluded. Of the 147 assessed patients receiving TNF blockers, 110 (75%) underwent QFT-G tests. A total of 126 (86%) patients used etanercept and 40 (27%) patients used adalimumab. Nineteen patients switched between both. Overall, patients had a median of 24 weeks (range 4-307) exposure to TNF blockers. Twelve patients (11%) who were treated with TNF blockers and eight (15%) without TNF blockers had positive QFT-G results. Of all TNF blocker users, only one patient (0·68%) developed tuberculosis. QFT-G can be used to screen for LTBI in a tuberculosis endemic area where bacille Calmette-Guérin vaccination coverage is high. Isoniazid prophylaxis is recommended for those who have positive QFT-G test results.

Questionable Effectiveness of the QuantiFERON-TB Gold Test (Cellestis) as a Screening Tool in Healthcare Workers

The Center for Disease Control and Prevention recommends the use of QuantiFERON TB Gold test (QFTG; Cellestis) in all situations where the tuberculin skin test (TST) is used. In November 2007, our institution replaced its screening-tool TST with the QFTG in-tube assay (QFT-GIT) for annual screening of latent tuberculosis infection among healthcare workers (HCWs). This study evaluated the effectiveness of QFT-GIT test as screening tool in HCWs at our institution. This retrospective study reviewed medical records of all HCWs who underwent screening with QFT-GIT from January 2008 through December 2008. Among the 6,530 HCWs screened with QFT-GIT from January through December 2008, 287 had a positive test result. Of the 287, 123 had positive TST results in the past, meaning that 164 HCWs had newly diagnosed latent tuberculosis infection by QFT-GIT. Of the 164 HCWs, 135 were retested by QFT-GIT and were simultaneously tested with TST within 4 weeks after the initial QFT-GIT. Of these 135 HCWs, 66 reverted to negative results and results remained positive for 69 with QFT-GIT. Only 2 HCWs had a positive TST result. The disagreement between QFT-GIT and TST results and the high reversion rate with QFT-GIT raise concerns about the effectiveness of QFT-GIT as a sole screening test in HCWs.

The use of positron emission tomography/CT in the diagnosis of tuberculosis-associated uveitis

BackgroundDetection of tuberculosis as the underlying disease in uveitis can be problematic because of the limited sensitivity of conventional diagnostic methods, especially in the case of latent infection. The aim...

Presumed Tuberculosis-induced Retinal Vasculitis, Diagnosed with Positron Emission Tomography (18F-FDG-PET/CT), Aspiration Biopsy, and Culture

Purpose: The diagnosis of tuberculosis as an etiological factor in patients with uveitis is difficult because of lack of specific diagnostic tests. The authors report 2 cases of occlusive retinal vasculitis, in which 18F-FDG-PET/CT was helpful for the diagnosis of tuberculosis as a presumptive cause of intraocular inflammation.Methods: In 2 patients with severe occlusive retinal vasculitis and positive QuantiFERON TB-Gold test, 18F-FDG-PET/CT, transbronchial needle-aspiration biopsy, and microbiological investigation were performed.Results: 18F-FDG-PET/CT showed increased fluorodeoxyglucose uptake in some mediastinal and hilar lymph nodes. After needle-aspiration biopsy of PET-positive lymph nodes, M. tuberculosis was recovered in culture in both cases. Remission of uveitis was achieved only after a combination therapy with 3 anti-tubercular agents and systemic steroids.Conclusion: The authors favor the use of 18F-FDG-PET/CT in patients with sight-threatening intraocular inflammation and positive interferon-gamma release assay. Anti-tubercular therapy, together with anti-inflammatory treatment, may lead to a remission in such patients.

Clinical utility of QuantiFERON TB Gold Test in the diagnosis of latent tuberculosis infections

Introduction: Early diagnosis of latent tuberculosis infection can avoid a progression to active tuberculosis.The interferon gamma (IFN-γ) production measured by the new interferon-gamma release assays (IGRAs) can be used to identify subjects with, because the tuberculin skin test, is unreliable to discriminative between subjects with and others. Methods: 186 patients tested positive with the tuberculin skin test were evaluated with QuantiFERON- TB Gold [QFT-G (Cellestis Ltd, Carnegie, Australia)]. Results: 61 (32.8%) samples showed a positive response with QFT-G test and only 1 (0.54%) patient tested indeterminate. Conclusion: These preliminary data suggest that QFT-G-positivity showed a strong correlation with clinical suspect of latent tuberculosis infection.

Costs of QuantiFERON®-TB Gold versus tuberculin skin test in Spanish healthcare workers

We compared the cost of the tuberculin skin test (TST) with the QuantiFERON-TB Gold (QFT-G) test when screening for latent tuberculosis in 134 healthcare workers in Spain. The QFT-G test cost euro42.5 per healthcare worker, while the TST cost euro39.5. The tests varied in cost structure; most (70%) TST costs were due to time demands on the participants, whereas the QFT-G was more expensive in terms of consumables (50% of the total cost). Accordingly, the results depend on the hourly wages of the participants and the time they must dedicate to the tests. In the Spanish healthcare system, the societal costs of QFT-G are comparable to those of the TST, although their cost structures are quite distinct.

Interest of QuantiFERON®‐TB (QT) Gold test (Cellestis) in patients with positive Tuberculin Skin Test (TST) in etiologic and therapeutic work‐up in uveitis

Abstract Purpose Define the interest of QuantiFERON®‐TB Gold test (Cellestis) in patients with positive Tuberculin Skin Test (TST) to improve etiologic and therapeutic work‐up in uveitis. Methods All patients followed in the Ophthalmology Department of Bicêtre Hospital between April 2007 and March 2009 for uveitis had an extensive work‐up including Tuberculin Skin Test (TST). Among them, 14 patients had a very positive TST making suspect an active tuberculosis infection. Then all of these patients had systematically a quantiFERON®‐TB Gold test. Finally, charts from clinical exam and therapeutic management were retrospectively analysed. Results The mean age at the time of presentation was 58 years (+/‐ 9) and sex ratio (F/M) was 43%. Uveitis was bilateral in 43% of cases, and the location of inflammation was anterior in 43% of the cases, intermediate (21.4%), posterior (21.4%) or total (7%). The average of PPD test was 21.75mm (+/‐ 4mm, 15‐65mm) and minimal delay between PPD and quantiFERON®‐TB Gold test was 3 days (mean: 42 days +/‐ 17). QuantiFERON®‐TB Gold test was positive in 9 patients (64.3%) enjoining introduction of a full anti‐tuberculosis therapeutic treatment in 8 patients (57.1%), that preceded oral steroids regimen in 42.8% of cases. Visual acuity increased dramatically (6 lines) in 4 patients and was unmodified for the others. Conclusion QuantiFERON®‐TB Gold test seems usefull in systematic diagnostic strategy in uveitis; it stays negative in 35.7% of the case suggesting that positive results are significant. However, further studies are necessary to define its place in diagnostic procedure in uveitis.

Comparison of Screening Procedures for Mycobacterium tuberculosis Infection Among Patients with Inflammatory Diseases

To test if Mycobacterium tuberculosis screening results differ among patients with inflammatory disease depending on whether the QuantiFeron TB-Gold test (QFT) or tuberculin skin test (TST) is used; and to evaluate if a possible difference is influenced by the presence of risk factors or immunosuppression. The interferon-gamma response to in vitro stimulation of M. tuberculosis-specific antigens was measured with QFT and results were compared with TST. Associations to bacillus Calmette-Guerin (BCG) vaccination, risk factors, and immunosuppression were analyzed for both tests. QFT and TST results were available for 294/302 and 241/302 patients, respectively; 234 had results from both tests. Twenty-one (7%) tested positive with QFT and 45 (19%) with TST. A positive QFT was associated with risk factors for M. tuberculosis infection: i.e., birth or upbringing in a TB-endemic area [risk ratio (RR) = 7.8, 95% CI 1.5-18.2, p < 0.001], previous TB treatment (RR 4.7, 95% CI 1.6-13.5, p = 0.005), and any latent TB infection risk factor (RR 4.7, 95% CI 2.1-11.0, p = 0.0002). Treatment with corticosteroids increased the risk for an inconclusive QFT result (RR 4.2, 95% CI 1.6-10.7, p = 0.04) and decreased the risk for a positive TST result (RR 0.4, 95% CI 0.1-1.0, p = 0.04). Agreement between the tests was low (kappa 0.2, 95% CI 0.02-0.3, p = 0.002). The study documented a high degree of discordant positive QFT and TST results. A positive QFT was more closely associated with risk factors for M. tuberculosis infection than the TST. The use of corticosteroids affected test outcome by increasing the risk for an inconclusive QFT result and decreasing the risk for a positive TST result.

S1134 Usefulness of the QuantiFERON TB Gold Test in Assessing the Necessity for TB Prophylaxis in IBD Patients Treated with Biologicals

S1134 Usefulness of the QuantiFERON TB Gold Test in Assessing the Necessity for TB Prophylaxis in IBD Patients Treated with Biologicals

P057 - Usefulness of the Quantiferon TB Gold Test in assessing the necessity for TB prophylaxis in IBD patients treated with biologicals

INTRODUCTION: Screening for latent tuberculosis is required prior to commencement of anti-TNF-alpha therapy in patients with IBD. However, the protein purified derivative (PPD) test is of low sensitivity and specificity in populations with high frequency of immunosuppressive treatment and previous BCG vaccination. AIMS &METHODS:We aimed to evaluate the usefulness of the Quantiferon TB Gold test in assessing the true necessity for TB prophylactic treatment. We performed an investigation on a group of our IBD patients by performing the screening for TB with all three tests: tuberculin skin test (PPD), chest X-ray (CXR), and Quantiferon TB Gold test (QTB). The primary goal of this study was to look at results of QTB in patients with slightly positive PPD (induration 5-15 mm), in whom the TB prophylaxis with isoniazide (INH) is recommended. In case of QTB negativity, this potentially hepatotoxic agent may be avoided, provided the CXR is also normal. RESULTS: One hundred and thirty four patients with both Crohn disease (CD) and ulcerative colitis (UC) were enroled. Among them, 24 (18%) had sligh positivity of the PPD, i.e. they had induration between 5-15 mm. Of these 24 subjects, 19 (79%) were QTB negative, 4 (17%) indeterminate, and 1 (4%) was QTB positive, respectively. None of 19 QTB negative patients was adviced by the pneumologist to be prophylactically treated with INH. On the other hand, there were 3 QTB positive patients among subjects with normal PPD (induration below 5 mm), all of them had also normal CXR. Despite this, they were given INH according to pneumologists' recommendation. Relatively more patients with QTB negativity were seen among those with normal PPD (96/104, 92%), as compared with group with slight PPD positivity (19/24, 79%). There was no positive QTB seen in patients with high PPD positivity (induration above 15 mm). CONCLUSION: Using the Quantiferon TB Gold test, the prophylactic INH administration could be avoided in almost 80% of patients with slightly positive PPD test. To the contrary, some 3% of PPD negative patients were identified to be at higher risk for TB, and therefore treated with INH.

Signification de Quantiféron TB Gold en tube en dépistage de la tuberculose parmi le personnel hospitalier en cas d’intradermoréactions positives très anciennes ou récentes

The tuberculin skin test or PPD performed on health professionals evaluates delayed hypersensitivity to a Mycobacterium tuberculosis (Mt) antigen mixture. A very positive or increased area of induration indicates latent tuberculosis. Yet, prescribing a treatment is often difficult because of the test's poor specificity.To determine if the T-lymphocytes of the proband exposed to specific Mt antigens to secrete interferon-gamma (IFN-gamma) can be measured; observe an immunizing response to cellular mediation improves T it this specificity?The Department of Occupational Health at CHR of Metz performed a Quantiferon TB Gold (tube method, Cellestis) test on three groups of employees distributed according to the anteriority of a very positive IDR (>15mm). The test measures by method ELISA, the quantity of IFN-gamma secreted by the lymphocytes T collected in 1ml of total blood, after in vitro stimulation by antigens ESAT-6, CFP-10 and TB7.7. Group I is composed of 53 people (46 women [W] and 7 men [M]) and related to a recent discovery of October 2006 and June 2007, whereas group II, includes 28 of them (25W and 3M), is made of subjects with known very positive PPD for eight to 27 years. The age (41 years on average) and the sex-ratio are identical for these two groups. Group III is made of employees having made a tuberculosis there is more than 30 years. In the group I, the rate of IFN was supervised at the end of the treatment among patients who received it.The test Quantiferon TB Gold was positive at 15 subjects of group I (13W and 2M), that is to say 28.3%, and unspecified in one case (1.9%); positive at nine subjects of group II (9W), that is to say 32.1%. These rates of positivity are not significantly different. According to the experts consulted in group I, an antituberculosis treatment was proposed 11 times with 10 effective treatments (one refusal). A proportioning after treatment was carried out among six patients. The rate of IFN remained positive at five of the six supervised patients. This test made it possible to avoid the treatment of the 37 employees with test Quantferon TB negative Gold found over the nine months period of recruitment of group I. The choice not to treat was facilitated.The test Quantiferon indeed allows to eliminate the false positive of the skin test (1.6) so avoiding useless, expensive treatments and unwanted effects of antituberculosis medicines . On the other hand, the persistent positivity of this test 30 years after one firstly infection or after a contact does not allow to use it at present as certain control of a latent infection, unless having a negative value known about the hiring pa.

QuantiFERON®-TB Gold test for healthcare workers

QuantiFERON®-TB Gold test for healthcare workers

Comment on: Use of the QuantiFERON TB Gold test as part of a screening programme in patients with RA under consideration for treatment with anti-TNF- agents: the Newcastle (UK) experience

Comment on: Use of the QuantiFERON TB Gold test as part of a screening programme in patients with RA under consideration for treatment with anti-TNF- agents: the Newcastle (UK) experience

QuantiFERON ®-TB Gold test in the identification of latent tuberculosis infection in immigrants

The identification and treatment of latent tuberculosis infection (LTBI) among immigrants are an effective strategy for TB control in developed countries. A new test for LTBI identification that uses more specific antigens of Mycobacterium tuberculosis is now commercially available under the brand name of QuantiFERON-TB Gold test. To compare QuantiFERON-TB Gold test to tuberculin skin testing (TST) for the detection of LTBI among immigrants from high endemic TB areas. Undocumented immigrants attending a district medical center were enrolled if they originated from high endemic TB areas, the time of arrival in Italy was < or = 5 years, had neither active TB disease nor known immunodeficiency status. The TST was applied according to standards and QuantiFERON-TB Gold test was performed following the manufacturer's instructions. Hundred subjects were included in the comparative analysis. TST was positive in 44% of subjects; 15% had a positive QuantiFERON-TB Gold test result. The total agreement between TST and QuantiFERON-TB Gold test was 71%, for a kappa statistics of 0.37; agreement was 100% for TST negative results, but only 34% for TST positive ones. In the multivariate logistic regression analysis, previous BCG vaccination was independently associated with a lower chance of disagreement between the tests. The prevalence of LTBI among immigrants was lower when determined by QuantiFERON-TB Gold; this may be a consequence of more specific MTB antigens used. Our results suggest that QuantiFERON-TB Gold may be used as confirmatory test for TST positive immigrants candidate to preventive therapy.

Use of the QuantiFERON TB Gold test as part of a screening programme in patients with RA under consideration for treatment with anti-TNF- agents: the Newcastle (UK) experience

Use of the QuantiFERON TB Gold test as part of a screening programme in patients with RA under consideration for treatment with anti-TNF- agents: the Newcastle (UK) experience

Detecting a low prevalence of latent tuberculosis among health care workers in Denmark detected by M. tuberculosis specific IFN-γ whole-blood test

The study was designed to estimate prevalence of tuberculosis infection among health care workers, using the tuberculin skin test (TST) and the new M. tuberculosis specific diagnostic whole-blood test and to identify possible risk factors. Employees at 2 departments of infectious diseases in Copenhagen were invited to enter the study. All attendants completed a questionnaire, had a TST and blood drawn for detection of interferon-gamma produced after stimulation with M. tuberculosis specific antigens ESAT-6 and CFP-10 (QuantiFERON-TB-Gold, Cellestis). 47 of 139 (34%) participants had a positive TST whereas only 2 of 139 (1%) had a positive QuantiFERON TB-Gold test (QFT-TB). 42 of 106 (40%) BCG vaccinated had positive TST (> or =12 mm) compared with 2 of 27 (7%) unvaccinated persons. Among 47 persons with positive TST, 42 (89%) were BCG- vaccinated. The 2 QFT-TB positive participants as well as the remaining 45 TST positive participants showed no sign of active tuberculous disease and were allocated to 6-month clinical follow-up, without medical therapy. Today, 1.5 y later, all remain healthy. The high rate of positive TST among health care workers was most probably due to BCG vaccination and not to infection with M. tuberculosis. The overall transmission rate determined by QFT-TB was found to be very low. The QFT-TB may be useful in distinguishing persons with latent TB infection from persons with positive TST due to BCG vaccination and its use may reduce anxiety.

Use of new TB test in children should be limited

A new diagnostic test called the "Quanti FERON - TB Gold test" for detection of tuberculosis infection has been introduced. Quanti FERON - TB Gold represents a significant advances and has some potential advantages compared to the tuberculin skin test (TST). OFT-G may be used in all circumstances in which TST is currently used including contact investigations and sequential-testing surveillance programs for infection control. The QFT-G test detects the release of interferon gamma. [IFN-g] in fresh heperinized whole blood when it is incubated with the synthetic peptides representing two proteins present in Myobacterium tuberculosis: early secretory antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10). The QFT-test kids include a positive (phytohemagglutinin) and negative (saline) control. The amount of antigen-specific IFN-g release is determined by subtracting the amount in the negative control from the amount in the ESAT-6 CFP-10 or positive control. Special software computes the corrected amounts and gives guidelines for the interpretations of the results. (excerpt)