Tuberculin Skin Test For Diagnosis Research Articles

Comparative performance evaluation of QIAreach QuantiFERON-TB and tuberculin skin test for diagnosis of tuberculosis infection in Viet Nam

Current WHO-recommended diagnostic tools for tuberculosis infection (TBI) have well-known limitations and viable alternatives are urgently needed. We compared the diagnostic performance and accuracy of the novel QIAreach QuantiFERON-TB assay (QIAreach; index) to the QuantiFERON-TB Gold Plus assay (QFT-Plus; reference). The sample included 261 adults (≥ 18 years) recruited at community-based TB case finding events. Of these, 226 underwent Tuberculin Skin Tests and 200 returned for interpretation (TST; comparator). QIAreach processing and TST reading were completed at lower-level healthcare facilities. We conducted matched-pair comparisons for QIAreach and TST with QFT-Plus, calculated sensitivity, specificity and area under a receiver-operating characteristic curve (AUC), and analyzed concordant-/discordant-pair interferon-gamma (IFN-γ) levels. QIAreach sensitivity and specificity were 98.5% and 72.3%, respectively, for an AUC of 0.85. TST sensitivity (53.2%) at a 5 mm induration threshold was significantly below QIAreach, while specificity (82.4%) was statistically equivalent. The corrected mean IFN-γ level of 0.08 IU/ml and corresponding empirical threshold (0.05) of false-positive QIAreach results were significantly lower than the manufacturer-recommended QFT-Plus threshold (≥ 0.35 IU/ml). Despite QIAreach’s higher sensitivity at equivalent specificity to TST, the high number of false positive results and low specificity limit its utility and highlight the continued need to expand the diagnostic toolkit for TBI.

Comparison of Interferon Gamma Release Assay and Tuberculin Skin Test for Diagnosis of Latent Tuberculosis in Psoriasis Patients Planned for Systemic Therapy.

Background:Latent tuberculosis infection (LTBI) is a common yet difficult problem to diagnose in tuberculosis endemic countries. Both tuberculin skin test (TST) and interferon-gamma release assay (IGRA) are used for the diagnosis of LTBI.Aims:The aim of the study is to compare TST and IGRA in patients planned for systemic treatment of psoriasis.Methods:It was a diagnostic study conducted in a tertiary care centre during the study period from January 20 to December 20. Patients more than 18 years of age with chronic plaque psoriasis planned for systemic therapy were included. Psoriasis area severity index (PASI), history of tuberculosis in past or family and BCG vaccination were recorded. Complete blood count, radiograph of the chest, tuberculin skin test and interferon-gamma release assay were performed in all patients. Statistical analysis was performed using statistical package for social sciences (SPSS version 20, Chicago).Results:A total of 75 patients, including 48 males and 27 females, were included in the study. The mean age and mean duration of disease were 46.08 (±12.16) and 4.59 (±3.8) years, respectively. Seventy-one (94.6%) patients had BCG scar, and two (2.6%) had a history of tuberculosis in a family member. The TST and IGRA were positive (>10 mm) in 23 (30.6%) and 16 (21.3%) patients, respectively. Either TST or IGRA was positive in 28 (37.3%) patients. Out of these 28 patients, concordance was seen in 11 (39.2%) and discordance in 17 (60.7%). Discordance was TST+/IGRA − in 12 (42.8%) and TST−/IGRA + in five (17.8%) patients. Abnormality in radiograph of the chest and computed tomography (CT) scan of the chest were seen in five (6.6%) and nine (12%) patients, respectively. The patients with either TST or IGRA + were more likely to have abnormal chest radiographs than those who were TST−/IGRA− (OR: 11.3, 95% CI: 1.24–102.3, P = 0.03). The TST and IGRA showed fair agreement ( = 0.364, P = 0.003). ROC curve was plotted for the absolute value of TST in mm considering IGRA as the gold standard. The area under the curve was 0.805 (95%CI: 0.655–0.954). For the TST positivity cut-off of 10 and 15 mm, specificity was 77.3% and 95.5%, respectively; the sensitivity was 68.8% irrespective of the cut-off value.Limitation:Small sample size and lack of follow-up are the biggest limitations of the study. The lack of a gold standard in the diagnosis of LTBI is an inherent yet unavoidable flaw in the study.Conclusion:Reactivation of LTBI is a concern in a patient planned for immunosuppressive therapy. We suggest the use of both TST and IGRA rather than two-step testing (TST followed by IGRA) or IGRA alone for the diagnosis of LTBI, especially in patients with a high risk of reactivation. The positivity on either test should prompt further evaluation and treatment decisions should be taken considering the risk-benefit ratio of treatment rather than test results alone.

Accuracy of the tuberculin skin test for diagnosis of latent tuberculosis in population with high coverage of Bacillus CalmetteÓ?Guérin vaccination

Accuracy of the tuberculin skin test for diagnosis of latent tuberculosis in population with high coverage of Bacillus CalmetteÓ?Guérin vaccination

Comparison between Quanti-FERON-TB Gold In-Tube test and tuberculin skin test for diagnosis of latent tuberculosis in children: A cross-section study

Objective: To compare Quanti-FERON-TB Gold In-Tube (QFT- GIT) test and tuberculin skin test (TST) for the diagnosis of latent tuberculosis infection in children. Methods: In this cross-sectional study, 64 participants who were between 3 months and 14 years old and had close contact with smear-positive pulmonary tuberculosis were included. Both QFT- GIT test and TST were done and the results were analyzed by SPSS software and Kappa test. Results: The distribution of gender and age according to QFT-GIT and TST results were matched (P>0.05). Overall agreement between QFT-GIT and TST for diagnosis of latent tuberculosis infection in children was 75%. In addition, the contingency coefficient was 0.257, and the Kappa measure of agreement was 0.246 (P=0.034). Conclusions: Compared to TST, QFT-GIT shows no apparent advantage for diagnosis of latent tuberculosis infection in children.

Cost-effectiveness of QuantiFERON-TB Gold In-Tube versus tuberculin skin test for diagnosis and treatment of Latent Tuberculosis Infection in primary health care workers in Brazil.

The goal of this study was to perform a cost-effectiveness analysis from the public health system perspective, comparing five strategies for Latent Tuberculosis Infection (LTBI) diagnosis in primary health care workers in Brazil. Analytical model for decision making, characterized by cost-effectiveness analysis. Primary Care Level, considering primary health care workers in Brazil. An analytical model for decision making, characterized by a tree of probabilities of events, was developed considering a hypothetical cohort of 10,000 primary health care workers, using the software TreeAge Pro™ 2013 to simulate the clinical and economic impacts of new diagnostic technology (QuantiFERON®-TB Gold in-Tube) versus the traditional tuberculin skin test. This model simulated five diagnostic strategies for LTBI in primary health care workers (HCW) in Brazil: tuberculin skin testing using ≥5 mm cut-off, tuberculin skin testing ≥10 mm cut-off, QuantiFERON®-TB Gold in-Tube, tuberculin skin testing using ≥5 mm cut-off confirmed by QuantiFERON®-TB Gold In-Tube if TST positive, tuberculin skin testing using ≥10 mm cut-off confirmed by QuantiFERON®-TB Gold In-Tube if TST positive. The outcome measures are the number of individuals correctly classified by the test and the number of Tuberculosis cases avoided. The most cost-effective strategy was the tuberculin skin test considering ≥10mm cut-off. The isolated use of the QuantiFERON®-TB Gold In-Tube revealed the strategy of lower efficiency with incremental cost-effectiveness ratio (ICER) of US$ 146.05 for each HCW correctly classified by the test. The tuberculin skin test using ≥10 mm cut-off was the most cost-effective strategy in the diagnosis of Latent Tuberculosis Infection in primary health care works in Brazil.

Screening for infectious diseases in newly arrived asymptomatic immigrants in southern Italy.

Screenings for infectious diseases in asymptomatic immigrants currently takes place when receiving new arrivals. We describe the frequency of infections in a cohort of newly arrived asymptomatic immigrants in Southern Italy. We studied a cohort of 238 Sub-Saharan African and Asian men hosted at a reception centre (CARA) in Foggia between January and December 2015. The tuberculin skin test for diagnosis of latent tuberculosis infection (LTBI) and serology/virology testing for HBV, HCV, HIV were performed. From this cohort, 205 individuals agreed to be tested for serological/virological markers only, while 82 agreed to be tested for LTBI only; 49 people agreed to have both tests. Among those tested for virological markers, 23/205 (11.2%) were HBsAg positive; 12/23 (52.2%) individuals had chronic active hepatitis; 77/205 (37.6%) individuals had only anti-HBc positivity. HCV infection was present in 8/205 (3.9%) individuals, and chronic HCV infection, was diagnosed in only two people. Only 2/205 (1.0%) individuals presented with anti-HIV and HIV-RNA positivity. We found LTBI in 29.6% of TB-tested individuals. Asymptomatic immigrants are at increased risk for some infections, mainly HBV and tuberculosis.

Comparison of Interferon-γ Release Assays and the Tuberculin Skin Test for Diagnosis of Tuberculosis in Human Immunodeficiency Virus: A Systematic Review.

BackgroundIt remains uncertain if interferon-γ release assays (IGRAs) are superior to the tuberculin skin test (TST) for the diagnosis of active tuberculosis (TB) or latent tuberculosis infection (LTBI) in immunosuppressed populations including people with human immunodeficiency virus (HIV) infection. The purpose of this study was to systematically review the performance of IGRAs and the TST in people with HIV with active TB or LTBI in low and high prevalence TB countries.MethodsWe searched the MEDLINE database from 1966 through to January 2017 for studies that compared results of the TST with either the commercial QuantiFERON-TB Gold in Tube (QFTGT) assay or previous assay versions, the T-SPOT.TB assay or in-house IGRAs. Data were summarized by TB prevalence. Tests for concordance and differences in proportions were undertaken as appropriate. The variation in study methodology was appraised.ResultsThirty-two studies including 4,856 HIV subjects met the search criteria. Fourteen studies compared the tests in subjects with LTBI in low TB prevalence settings. The QFTGT had a similar rate of reactivity to the TST, although the first-generation version of that assay was reactive more commonly. IGRAs were more frequently positive than the TST in HIV infected subjects with active TB. There was considerable study methodology and population heterogeneity, and generally low concordance between tests. Both the TST and IGRAs were affected by CD4 T-cell immunodeficiency.ConclusionOur review of comparative data does not provide robust evidence to support the assertion that the IGRAs are superior to the TST when used in HIV infected subjects to diagnose either active TB or LTBI.

T-SPOT. TB assay and tuberculin skin test for diagnosis and screening of tuberculosis: First report in a Sri lankan population

Objective: Guidelines encourage evaluation of an Interferon Gamma Release Assay (IGRA) in the local setting, particularly in low/ middle income, Bacillus Calmette Guerin (BCG) vaccinated populations where the assays have shown variable utility. The TSPOT.TB assay and the Tuberculin Skin Test (TST) were compared in diagnosis of active tuberculosis (TB) and in contact screening in an adult Sri Lankan population.Methods: A prospective study including confirmed TB cases (n=75), controls (n-74) and close contacts of smear positive cases (n=27) was carried out at the regional Chest clinic in Kandy district. Clinical history and investigation findings, including TST results were recorded and the TSPOT.TB (Oxford Immunotec) performed.Results: The presence of diabetes and cavitation were significant predictors of TSPOT.TB positivity, while TST had no significant clinical predictors. In the diagnosis of active TB, TSPOT.TB sensitivity was 73.3% (95% CI, 58.6-84.6%) and a specificity was 72% (95% CI, 62.0-85.5%) while the TST sensitivity was 70.7% (95% CI, 54.2-83.3%) and specificity was 64.1% (95% CI, 49.7-76.5%). In contact investigation neither test showed an association with exposure level. Cost estimate was LKR 9400.00 per TSPOT.TB test compared to LKR 200.00 per TST. A high (21%) indeterminate result rate was seen with the TSPOT.TB assayConclusions: This study did not show any advantage in using TSPOT.TB over TST in this setting.Asian Journal of Medical Sciences Vol.7(1) 2015 14-19

Comparison of an interferon-gamma release assay and the tuberculin skin test for diagnosis of latent tuberculosis in homeless people in Iran: a cross-sectional study

Background: The aim of this study was to evaluate of the concordance between the results of the tuberculin skin test (TST) and an interferon-γ release assay (QuantiFERON test, QFT-GIT) for diagnosis of latent tuberculosis infection (LTBI) in homeless people in Tehran city, Iran. Methods: This cross-sectional study was conducted from June to August 2012. Homeless people were eligible to participate in the study if they were 18–60 years old. Results: Among 569 homeless people, 46.22% (95% confidence interval (CI) = 42.16–50.33%) and 20.39% (95% CI = 17.28–23.9%) were QFT-GIT and TST positive, respectively. Among these participants, the prevalence of LTBI with positivity of at least one of the tests was 52.2%. The overall agreement between QFT-GIT and TST was 62.21% (kappa = 0.21, 95% CI = 0.13–0.29, p < 0.001). Factors associated with positive results in QFT-GIT and TST were older age, being male, having a longer history of homelessness and having a history of incarceration in the last 10 years. Conclusions: A high prevalence of LTBI was seen among homeless people in this study. There was a poor concordance between QFT-GIT and TST among this group. To better assess the utility of QFT-GIT in detection of LTBI further studies with a low prevalence of LTBI in this group are recommended.

Performance of QuantiFERON-TB Gold In-Tube test and Tuberculin Skin Test for diagnosis of latent tuberculosis infection in BCG vaccinated health care workers

BackgroundTuberculin skin test (TST) has been used for years as an aid in diagnosing latent tuberculosis infection (LTBI) but it suffers from a number of well-documented performance and logistic problems. Quantiferon-TB Gold In Tube test (QFT-GIT) has been reported to have better sensitivity and specifity than TST. In this study, it was aimed to compare the performance of a commercial IFN-γ release assay (QFT-GIT) with TST in the diagnosis of HCWs at risk for latent TB infection in BCG vaccinated population.Material/MethodsHundred healthy volunteer health care workers were enrolled. All were subjected to TST and QFT-GIT. Results were compared among Health Care Workers (HCWs) groups in terms of profession, workplace, working duration.ResultsTST is affected by previous BCG vaccinations and number of cases with QFT-GIT positivity is increased in accordance with the TST induration diameter range. QFT-GIT result was negative in 17 of 32 TST positive (≥15 mm) cases and positive in 4 of 61 cases whose TST diameters are between 6–14 mm, that is attritutable to previous BCG vaccination(s). It was negative in all cases with TST diameters between 0–5 mm.HCWs with positive QFT-GIT results were significantly older than the ones with negative results. Furthermore duration of work was significantly longer in QFT-GIT positive than in negative HCWs.ConclusionsThere was a moderate concordance between QFT-GIT and TST, when TST result was defined as positive with a ≥15 mm diameter of induration. We suggest that QFT-GIT can be used as an alternative to TST for detection of LTBI, especially in groups with high risk of LTBI and in population with routine BCG vaccination program.

Effect of micronutrient deficiency on QuantiFERON-TB Gold In-Tube test and tuberculin skin test in diagnosis of childhood intrathoracic tuberculosis

Data on performance of QuantiFERON-TB Gold In-Tube test (QFT) and tuberculin skin test (TST) in children with active tuberculosis from high burden countries in the context of micronutrient deficiency are scarce. The objective of this study was to evaluate the effect of micronutrient deficiency on the performance of TST and QFT in children with intrathoracic tuberculosis. Children with probable intrathoracic tuberculosis underwent TST, QFT, gastric lavages and induced sputum examination for AFB (Acid-Fast Bacilli) smear and culture. Zinc, copper, ferritin and vitamin D were measured on stored serum samples. The study used cross-sectional data at initiation of anti-tubercular therapy. Three hundred and sixty-two children (median age 115.5 months (interquartile range: 73, 144), 200 (55.3%) girls) were enrolled in the study. Microbiological confirmation of tuberculosis could be obtained in 128 patients. TST and QFT were positive in 337 (93%) and 297 (82%) children, respectively. Performance of both the tests was unaffected by weight-for-age and height-for-age 'z-scores' or by serum copper levels. TST was not affected by serum zinc and ferritin levels. Children with negative QFT results had lower mean serum zinc level (P=0.01) and higher ferritin levels (P=0.007) as compared to those with positive test. Higher proportion of children with positive TST were vitamin D deficient/insufficient (P=0.003). Micronutrient status, especially serum levels of zinc, may influence the performance of QFT in children with intrathoracic tuberculosis. Considering the high prevalence of zinc deficiency in developing countries, QFT should be used cautiously for diagnosing tuberculosis.

Comparative study between using QuantiFERON and tuberculin skin test in diagnosis of Mycobacterium tuberculosis infection

AimStudy degree of sensitivity and specificity of IFN-γ as QuantiFERON-TB Gold In-Tube assay in diagnosis of tuberculosis instead of tuberculin test. Subjects and methodsForty patients were included in this study subdivided into two groups. First included 20 patients with sputum positive for tuberculosis, while the second included 20 patients suspected to catch TB infection, guided by: clinical and radiological examinations with smear negative for TB. Control group included 10 clinical and radiological healthy controls previously vaccinated by BCG with positive tuberculin test. All subjects were submitted for full clinical history physical examination routine laboratory tests, plain chest X-ray, sputum study for acid fast Bacilli by Ziehl–Neelsen stain, tuberculin test using Mantoux technique, sputum culture on Lowenstein-Jensen Medium and QuantiFERON-TB Gold In-Tube (QFT-Gold IT) assay. ResultsQFT-Gold IT test sensitivity=100% specificity=100% predictive value positive=100% which means that 100% of the disease positive patients gave positive QFT-Gold IT test and predictive value negative=100% which means that 100% of the disease negative patients gave negative QFT-Gold IT test. Agreement between tuberculin test and QFT-Gold IT test was good agreement where the ‘κ’ was 0.65 (CI=0.39–0.91). Study revealed positive correlation between QuantiFERON level and severity of infection in sputum, which was statistically significant, where ‘r’ was 0.92 and P-value was <0.05. ConclusionQFT-Gold IT, has excellent sensitivity and specificity unaffected by BCG vaccination. Tuberculin test specificity is high in non-BCG-vaccinated populations but low and variable in BCG vaccinated populations.

Commercial Interferon Gamma Release Assays Compared to the Tuberculin Skin Test for Diagnosis of Latent Mycobacterium tuberculosis Infection in Childhood Contacts in the Gambia

We compared the performance of tuberculin skin test (TST), Quantiferon-TB Gold in-tube (QFT-GIT), and T-SPOT.TB in diagnosing latent tuberculosis (LTBI) among childhood TB contacts in a TB endemic setting with high BCG coverage. We evaluated the performance of interferon gamma release assays (IGRAs) and TST when combined in an algorithm. Childhood contacts of newly diagnosed TB patients were tested with TST, QFT-GIT, and T-SPOT. The level of exposure in contacts was categorized according to whether they slept in the same room, same house, or a different house as the index case. For the evaluation of combined test performance, prior estimates for prevalence of latent TB were used in Bayesian models that assumed conditional dependence between tests. A total of 285 children were recruited. Overall, 26.5%, 33.0%, and 33.5% were positive for TST, T-SPOT, or QFT-GIT, respectively. All 3 tests responded to the gradient of sleeping proximity to the index case. Neither TST nor IGRA results were confounded by BCG vaccination. There was moderate agreement (kappa = 0.40-0.68) between all 3 tests. Combination of either IGRA with TST increased sensitivity (by 9.3%-9.6%) especially in contacts in the highest exposure category but was associated with loss of specificity (9.9%-11.3%). IGRAs and TST are similar in their diagnostic performance for LTBI. An approximate 10% sensitivity benefit for using the TST and an IGRA in combination is associated with a slightly greater specificity loss. Testing strategies combining an IGRA and TST with an "or" statement may be useful only in situations where there is a high pretest probability of latent infection.

Comparison of in vitro-specific blood tests with tuberculin skin test for diagnosis of latent tuberculosis before anti-TNF therapy

Introduction:Latent tuberculosis infection (LTBI) is detected with the tuberculin skin test (TST) before anti-TNF therapy. We aimed to investigate in vitro blood assays with TB-specific antigens (CFP-10, ESAT-6), in immune-mediated...

Comparison of T-cell-based assay with tuberculin skin test for diagnosis of Mycobacterium tuberculosis infection in a school tuberculosis outbreak

The diagnosis of latent tuberculosis infection relies on the tuberculin skin test (TST), which has many drawbacks. However, to find out whether new tests are better than TST is difficult because of the lack of a gold standard test for latent infection. We developed and assessed a sensitive enzyme-linked immunospot (ELISPOT) assay to detect T cells specific for Mycobacterium tuberculosis antigens that are absent from Mycobacterium bovis BCG and most environmental mycobacteria. We postulated that if the ELISPOT is a more accurate test of latent infection than TST, it should correlate better with degree of exposure to M tuberculosis. A large tuberculosis outbreak in a UK school resulted from one infectious index case. We tested 535 students for M tuberculosis infection with TST and ELISPOT. We compared the correlation of these tests with degree of exposure to the index case and BCG vaccination. Although agreement between the tests was high (89% concordance, kappa=0.72, p<0.0001), ELISPOT correlated significantly more closely with M tuberculosis exposure than did TST on the basis of measures of proximity (p=0.03) and duration of exposure (p=0.007) to the index case. TST was significantly more likely to be positive in BCG-vaccinated than in non-vaccinated students (p=0.002), whereas ELISPOT results were not associated with BCG vaccination (p=0.44). ELISPOT offers a more accurate approach than TST for identification of individuals who have latent tuberculosis infection and could improve tuberculosis control by more precise targeting of preventive treatment.

Two-step tuberculin skin test in nurse students and hospital employees

Booster phenomenon (recall effect) of tuberculin skin test, which disturbs diagnosis of tuberculous infection, is prevalent among BCG vaccinated population. We retested 34 nurse students whose initial tuberculin reaction was smaller than 30 mm by erythema (Group A) and 53 hospital employees whose initial reaction was smaller than 20 mm by erythema (Group B). Among the people whose diameter of erythema was less than 10 mm by the first test, 88 percent (8/9) of group A and 43% (6/14) of group B showed reaction 10 mm < or = by erythema and among those whose induration was < 10 mm, 54% (6/11) of group A and 48% (12/25) of group B showed reaction 10 mm < or = in the second testing. Mean and standard deviation of [the difference between the diameter of the 2nd and the 1st testing] was +7.3 +/- 11.8 mm in group A, +9.8 +/- 11.1 mm in group B by erythema and +2.6 +/- 5.9 mm in group A, +2.9 +/- 5.1 mm in group B by induration. These results indicate that booster phenomenon is highly prevalent among the tested group and there can be no appropriate criteria to distinguish new infection and booster phenomenon. Though two-step tuberculin skin test is recommended to get rid of booster phenomenon. Only a little is known about the value of this test to diagnose new infection in Japanese population, majority of whom being BCG vaccinated. Further investigations are required to apply two-step tuberculin skin test for diagnosis of new infection among hospital employees and health care workers in Japan.