Prevalence of Latent Tuberculosis Infection Among Healthy Young Children and Adolescents and a Two-step Approach for the Diagnosis of Tuberculosis Infection in Chengdu, China.

BACKGROUND: China has a high burden of tuberculosis and latent tuberculosis infection (LTBI). The aim of this study was to estimate the prevalence of LTBI among healthy young children and adolescents and test a 2-step approach to explore the threshold for the diagnosis of tuberculosis infection in Chengdu, China. METHODS: Healthy preschool children and school-going children in Chengdu, Sichuan Province, were screened for LTBI using the tuberculin skin test (TST). Preschool children with TST ≥ 5 mm also underwent interferon-γ release assay (IGRA) to explore the threshold of this 2-step approach. RESULTS: In total, 5667 healthy young children and adolescents completed TST test between July 2020 and January 2021 and were included in the present analysis. The age of the participants ranged from 2.4 to 18 years (median 7.25 ± 4.514 years), of which 2093 (36.9%) were younger than 5 years. The overall prevalence of LTBI was 6.37% and 6.64% in children younger than 5 years old. Fourteen of the 341 preschool children with TST ≥5 mm were interferon-γ release assay positive, of which 4 showed a TST result of 5-10 mm, and 6 preschool children received preventive treatment for LTBI. CONCLUSIONS: Healthy young children and adolescents should also be considered as important target populations for LTBI screening. TST can be recommended for first-line screening as part of a 2-step approach for LTBI screening using a positive threshold of 5 mm.

Epidemiology, clinical features and outcomes of incident tuberculosis in children in Canada in 2013-2016: results of a national surveillance study.

PURPOSE: Childhood tuberculosis disease is difficult to diagnose and manage and is an under-recognised cause of morbidity and mortality. Reported data from Canada do not focus on childhood tuberculosis or capture key epidemiologic, clinical and microbiologic details. The purpose of this study was to assess demographics, presentation and clinical features of childhood tuberculosis in Canada. METHODS: We conducted prospective surveillance from 2013 to 2016 of over 2700 paediatricians plus vertical tuberculosis programmes for incident tuberculosis disease in children younger than 15 years in Canada using the Canadian Paediatric Surveillance Program (CPSP). RESULTS: In total, 200 cases are included in this study. Tuberculosis was intrathoracic in 183 patients of whom 86% had exclusively intrathoracic involvement. Central nervous system tuberculosis occurred in 16 cases (8%). Fifty-one per cent of cases were hospitalised and 11 (5.5%) admitted to an intensive care unit. Adverse drug reactions were reported in 9% of cases. The source case, most often a first-degree relative, was known in 73% of cases. Fifty-eight per cent of reported cases were Canadian-born Indigenous children. Estimated study rates of reported cases (per 100 000 children per year) were 1.2 overall, 8.6 for all Indigenous children and 54.3 for Inuit children. CONCLUSION: Childhood tuberculosis may cause significant morbidity and resource utilisation. Key geographies and groups have very high incidence rates. Elimination of childhood tuberculosis in Canada will require well-resourced community-based efforts that focus on these highest risk groups.

IgG4-Related Disease With Tuberculosis: A Case Report and Retrospective Review of Patients in a Single Center.

Background: IgG4-related disease (IgG4-RD) is a recently recognized systemic fibro-inflammatory disease of unknown cause involving many organs including pancreas, salivary glands, and lymph nodes. Chronic tuberculosis (TB) infection has been reported in IgG4-RD, but the prevalence of TB infection has not been evaluated in IgG4-RD. Methods: Characterization of a patient with IgG4-RD by physical examination, laboratory tests, magnetic resonance imaging (MRI) and histological examination. TB infection was evaluated by medical history, radiological examinations, sputum examinations, tubercular skin test (TST) and interferon gamma (IFN-γ) release assay test (IGRA). Medical records of IgG4-RD patients were reviewed in our institute from February 2015 to September 2020 to explore the prevalence of TB infection in IgG4-RD. Results: We described a 40-year-old Chinese man presented with headache and diplopia. Physical examination revealed bitemporal hemianopsia and limited abduction of both eyes. MRI revealed uniformly enhancing mass overlying clivus with dural tail sign. Laboratory data revealed elevation of IgG4 (1.9g/L), and TB-IGRA demonstrated significantly elevated IFN-γ (414.21 pg/ml). The clivus lesion was subtotally removed and IgG4 was strongly positive on immunohistochemical staining. The diagnosis of IgG4-RD was established, and the patient received treatment of corticosteroids, methotrexate, and cyclophosphamide with isoniazid prophylaxis. Consequently, the mass shrank remarkably within 3 months. A similar concurrence of TB disease or latent TB infection (LTBI) and IgG4-RD was present in 17/47 (36.2%) patients in our institute. Conclusion: High frequency of TB/LTBI presented in patients with IgG4-RD. Patients with IgG4-RD and LTBI should be closely monitored for resurgence of TB. Whether TB represents a risk for IgG4-RD should be further investigated in prospective cohort.

Preliminary observations on IGRA testing for TB infection in patients with severe COVID-19 eligible for immunosuppressive therapy.

COVID-19, the novel coronavirus pandemic, has already spread around the globe affecting more than 18 million people. As previously observed with other coronaviruses, SARS-CoV-2 deeply dysregulate the immune system eliciting respiratory failure and a state of systemic hyperinflammation in severely ill individuals. Immunotherapy is often used to downgrade the detrimental effects of the disease sustained by high-level of cytokines. Those treatments, however, are known to undermine patients' ability to contain tuberculosis (TB) infection. This study aims to describe interferon-γ release assay (IGRA) results in severe COVID-19 patients eligible for immunosuppressive treatment. Aggregate data were gathered from five hospitals in Milan, Italy, from March 1 to May 15, 2020 and retrospectively analyses. Results were summarized using absolute frequencies and percentages and compared using a two-sided Chi-squared test. Overall, 462 COVID-19 patients were eligible for immunosuppressive therapy, among which 335 were tested using IGRA testing. More than one-third of them (122/335; 36.4%) had an indeterminate IGRA result because of insufficient immune response to mitogen control, 19 (5.7%) tested positive and 194 (57.9) negative. The majority of patients with lymphocytopenia (i.e., total lymphocyte count [TLC] below 1000 cells/mm3) had indeterminate IGRAs (81/155; 52.3%). The proportion becomes even higher in patients with severe lymphocytopenia (i.e., TLC<500 cells/mm3) (36/57; 63%). Our results suggest a possible negative impact of COVID-19 related immune dysregulation on TB infection assessment and management. Close monitoring of individuals with or without retesting of individuals with indeterminate IGRAs and further basic science investigations should to be sought to better comprehend their implication on TB epidemiology.

Interferon-γ Release Assays for Tuberculosis Infection Diagnosis in Refugees <5 Years Old.

BACKGROUND: New guidelines support using interferon-γ release assays (IGRAs) in children ≥2 years for diagnosis of latent tuberculosis infection (LTBI). However, lack of experience in young children and concern that IGRAs are less sensitive than tuberculin skin tests (TSTs) limit their use. Our aim was to identify active tuberculosis (TB) cases among high risk children <5 years and tested for LTBI with an IGRA. METHODS: . Retrospective review of domestic TB screening data from California's Refugee Health Electronic Information System for children <5 years old who resettled in California between October, 2013 and December, 2016. Children were crossmatched with the California TB registry to identify cases of TB disease between October 2013 and December 2018. RESULTS: A total of 3371 children <5 years were identified; the majority were born in countries with high TB incidence (>150 cases per 100 000). Half received IGRAs (n = 1878; 56%), a quarter received TSTs (n = 811; 24%); 1.4% of children were IGRA-positive (n = 26) and 13% were TST-positive (n = 106). Twenty-two IGRA results were indeterminate (1.2%). Sixteen children had both tests; 9 were discrepant (positive TST with negative IGRA). No cases of TB disease were identified during 10 797 person-years of follow-up. CONCLUSIONS: IGRA positivity was less than TST positivity in high risk children <5 years old. Despite fewer LTBI diagnoses in the IGRA-tested population, no cases of TB disease among children who tested negative were identified, suggesting IGRA is valuable tool for identifying LTBI in this population.

Interferon-Gamma Release Assay Testing in Children Younger Than 2 Years in a US-Based Health System.

BACKGROUND: Use of interferon-gamma releasing assays (IGRAs) in children <2 years old may derive many of the same advantages, which have led to preference over tuberculin skin test (TST) in older children, but data are limited. Since 2011, we have tested children <2 years old with Quantiferon-TB Gold/Gold Plus (QFT)) in select clinical scenarios at Denver Health, a health system encompassing a TB clinic, refugee and immigrant screening and primary care. METHODS: We identified patients <2 years old tested with QFT between February, 2011 and August, 2019. The primary outcome measure was incident cases of TB among tested patients. Test results and in vitro characteristics were analyzed, as were demographic, epidemiologic and clinical outcomes. RESULTS: We analyzed 116 QFTs ordered in children age 7-23 months. Two were positive, 3 indeterminate, 3 failed/refused phlebotomy and the remainder (93%) were negative. Mitogen tube results were robust. Thirteen patients were TST-positive: 11 were QFT-negative, 1 QFT-positive and 1 failed phlebotomy. Eight patients received some form of TB medication, including 4 QFT-negative patients who were treated for active TB or latent TB infection based on positive TST or clinical findings. Among QFT-negative patients, including 6 TST-positive, not treated for active TB or latent TB infection, no TB disease has been identified over a median follow-up time of 2.96 years. CONCLUSIONS: IGRA use was not limited by barriers of phlebotomy, indeterminate result or gamma-interferon production. The risk of missing an infected but IGRA-negative patient can be reduced by treatment of select patients at higher risk. Current recommendations against IGRA use in children <2 years old could be amended to allow careful introduction, particularly among well-appearing BCG-vaccinated patients.

The use of a borderline zone for the interpretation of interferon-gamma release assay results for serial screening of healthcare workers.

OBJECTIVE: An interferon-gamma release assay (IGRA) is used to screen for latent tuberculosis infection (LTBI). Among IGRAs, the QuantiFERON-TB Gold In-Tube (QFT-GIT) results are highly variable, so the borderline zone has been proposed to reduce unnecessary LTBI treatment. The aim of this study was to examine the proportion of the borderline zone of QFT-GIT in healthcare workers' (HCWs) serial IGRA and to retrospectively identify the utility of predicting tuberculosis (TB) in a moderate TB incidence setting. METHODS: The participants were HCWs who had undergone serial LTBI screening between June 2013 and June 2018. IGRA-positive HCWs underwent examinations that included low-dose computed tomography (LDCT) and TB culture, if necessary. Applying the borderline zone (0.2-<0.7 IU/mL), the results were classified as definite negative, borderline negative, borderline positive and definite positive. RESULTS: Through the follow-up of 477 HCWs, 441 (92.5%) invariant, 30 (6.3%) conversion, 2 (0.4%) reversion and 5 (1.0%) indeterminate results were observed with the manufacturer's cutoff. Applying the borderline zone, 419 (87.8%) invariant, 22 (4.6%) conversion, 1 (0.2%) reversion and 36 (7.5%) decision pending, including 5 (1.0%) indeterminate results, were observed. At the time of screening, five TB cases were identified. Chest X-ray (CXR) identified one TB case, and LDCT identified four additional TB cases. After one year, two TB cases were diagnosed, and their screening QFT-GIT results were definite positive and borderline negative. In the Cochran-Armitage trend test, the greater the maximum difference in the QFT-GIT grade with the borderline zone was, the higher the probability of developing TB (P-value <0.001). CONCLUSION: The application of the borderline zone lowered the conversion rate but increased the decision pending rate. Introducing the borderline zone requires a careful approach, and a thorough examination needs to be performed to rule out TB in converters. HCWs with borderline QFT-GIT results also need close observation.

Comparison between the Interferon γ Release Assay-QuantiFERON Gold Plus (QFT-Plus)-and Tuberculin Skin Test (TST) in the Detection of Tuberculosis Infection in Immunocompromised Children.

BACKGROUND: Immunocompromised patients are at a higher risk of having latent tuberculosis infection (LTBI). QuantiFERON-TB Gold Plus (QFT-Plus) has been proven to perform effectively in LTBI detection among immunocompromised adults and can overcome the limitations of the tuberculin skin test (TST). However, the role of QFT-Plus in detecting LTBI in immunocompromised paediatric patients has not been well established. Therefore, the aim of this study was to assess the test agreement between QFT-Plus and the TST in LTBI detection among immunocompromised children. METHOD: In this cross-sectional study, we enrolled immunocompromised paediatric patients, aged between 5 and 18 years, who were treated with corticosteroids and/or chemotherapy from June to November 2019. We categorized them into three groups based on the following diseases: hematologic malignancies and nephrological and immunological diseases. We recorded the patient characteristics and QFT-Plus and TST results, in which the positive result of the TST was induration ≥ 5 mm. Within the same group, comparisons between the two tests were performed using the McNemar test, and results were statistically significant for p values of <0.05. The kappa index was used to assess the agreement between the two test results. RESULTS: Among 71 patients (median age: 11.8 years) who underwent TST and QFT-Plus testing, 52% were females, and 69% had a normal nutritional status. Chemotherapy was the most common treatment modality for hematologic malignancy compared to other immunosuppressive treatments. The total number of patients with positive QFT-Plus and TST results was 11/71 (15.5%) and 4/71 (5.6%), respectively, among whom 3/11 patients had positive results in both tests, and one patient with positive TST results exhibited a discrepancy, as this was not followed by positive QFT-Plus results. QFT-Plus generated more positive results than the TST in immunocompromised children (McNemar, p = 0.039 (p < 0.05)). The diagnostic agreement between the tests was fair (K = 0.345, 95% CI: 0.05-0.745). CONCLUSION: QFT-Plus detected LTBI more effectively than the TST in immunocompromised children.

Tuberculosis Infection Among People With Diabetes: United States Population Differences by Race/Ethnicity.

INTRODUCTION: Diabetes might confer a modestly increased risk of latent tuberculosis infection, which without treatment can progress to active tuberculosis disease. Three recent analyses of the National Health and Nutrition Examination Survey found a positive association between diabetes and a positive test for Mycobacterium tuberculosis infection. This study examines whether prevalence of a positive test still varies by diabetes status after stratifying by race/ethnicity. METHODS: This cross-sectional analysis used the public-use National Health and Nutrition Examination Survey 2011-2012 data sets and was conducted in 2018-2019. Interview and examination results for 5,560 adult participants yielded estimates for 219 million U.S. adults in the 4 largest race/ethnicity groups. The weighted prevalence of positive tuberculin skin test or interferon-gamma release assay by diabetes status was ascertained in each group. RESULTS: Among white and black adults, diabetes was associated with no difference in positive skin test prevalence and little difference in positive interferon-gamma release assay prevalence. The positive assay prevalence difference was +14.5% (95% CI=2.3%, 26.7%) among Hispanic and +9.9% (95% CI=1.2%, 18.6%) among Asian adults, when comparing those with diabetes with those with neither diabetes nor prediabetes. Based on assay results, 23.6% (95% CI=14.0%, 36.9%) of Hispanic and 27.2% (95% CI=19.6%, 36.5%) of Asian adults with diabetes also had latent tuberculosis infection. CONCLUSIONS: Hispanic and Asian subpopulation results drove much of the previously reported positive association between diabetes and a positive test for M. tuberculosis infection. Hispanic and Asian adults with diabetes might particularly benefit from screening and treatment for latent tuberculosis infection.

Host factors associated to false negative and indeterminate results in an interferon-γ release assay in patients with active tuberculosis.

INTRODUCTION: Information on host factors that contribute to false negative and indeterminate results in interferon-γ release assays (IGRA) are critical to improve the usefulness of these tests in the fight against tuberculosis (TB) epidemics. The aim of this study was to estimate and compare the sensitivity of an IGRA and the tuberculin skin test (TST), independently and as a combined approach, in patients with TB and to identify risk factors associated with false negative and indeterminate IGRA results. METHODS: Retrospective cohort study of all active TB notifications with an IGRA result (n = 1230), from 2008 to 2015. 68.0 % (n = 727) of these patients had a TST result interpreted using a 5 mm (TST-5 mm) and 10 mm (TST-10 mm) cutoff. Sensitivity was determined for both tests. Logistic regression analysis was used to evaluate the association of sociodemographic and clinical factors to the risk of false negative or indeterminate IGRA results. RESULTS: IGRA, TST-5 mm and TST-10 mm were positive in 82.4 %, 84.5 % and 78.4 % of the patients that performed both tests. When used combined, IGRA/TST-5 mm sensitivity was 91.7 % and IGRA/TST-10 mm sensitivity was 90.6 %. Age≥65 years, alcohol abuse and pulmonary TB were predictive factors for indeterminate results. Inflammatory diseases and pulmonary TB were statistically associated with false negative IGRA results. CONCLUSION: Inflammatory diseases and pulmonary TB were identified as factors for false negative IGRA results. Our results indicate that the use of both tests in a combined approach, especially in specific risk groups of the population, could increase the sensitivity of the screening process and accelerate the achievement of the WHO End TB Strategy goals.

Mycobacterium tuberculosis infection in psoriatic patients treated with biologics: Real-world data from 18 Japanese facilities.

Although rare, tuberculosis has been reported with biologic treatment against psoriasis in Japan, a tuberculosis medium-burden country. Mycobacterial infection often develops after a long incubation period and might not have been adequately identified in clinical trials or post-marketing surveillance. To determine the real-world incidence of tuberculosis in psoriatic patients treated with biologics, we conducted a retrospective, multicenter, observational study in 18 facilities in Western Japan. Psoriatic patients who visited a participating facility between 2010 and March 2017 and received biologic reagents were enrolled. Information on sex, age at first biologic treatment, results of interferon-γ release assay (IGRA) for Mycobacterium tuberculosis, treatment history with isoniazid, and onset of active and/or latent tuberculosis was collected. A total of 1117 patients (830 men and 287 women) were enrolled. The mean duration of biologic treatment was 3.54 years. Sixty-five patients (5.8%) showed positive IGRA results at screening. Active tuberculosis developed in two patients after the administration of tumor necrosis factor inhibitors (both involved miliary tuberculosis). Latent tuberculosis was observed in two patients treated with anti-interleukin-12/23p40 antibody. The incidence rate of tuberculosis, including latent tuberculosis, in this survey was 0.36%. Although the incidence rate of tuberculosis was low considering the observation period of biologic treatment, active tuberculosis was found in both the screening-negative group and a screening-positive subject after isoniazid prophylaxis (both miliary tuberculosis), concluding that negative screening or isoniazid treatment does not always assure that an individual has no tuberculosis. Hence, dermatologists still need to pay careful attention to tuberculosis at every patient visit.

BCG revaccination boosts adaptive polyfunctional Th1/Th17 and innate effectors in IGRA+ and IGRA- Indian adults.

BACKGROUNDBacille Calmette-Guérin (BCG) vaccine is protective against Tuberculosis (TB) in children, but its efficacy wanes with age. Consequently, determining if BCG revaccination augments anti-TB immunity in young adults in TB endemic regions is vital.METHODSTwo hundred healthy adults, BCG vaccinated at birth, were tested for their IFN-γ release assay (IGRA) status. Of these, 28 IGRA+ and 30 IGRA- were BCG revaccinated, and 24 IGRA+ and 23 IGRA- subjects served as unvaccinated controls. T and innate cell responses to mycobacterial antigens were analyzed by 14-color flow cytometry over 34 weeks.RESULTSIFN-γ and/or IL-2 Ag85A- and BCG-specific CD4+ and CD8+ T cell responses were boosted by revacciantion at 4 and 34 weeks, respectively, and were > 2-fold higher in IGRA+ compared with IGRA- vaccinees. Polyfunctional Ag85A, BCG, and mycobacterium tuberculosis (Mtb) latency Ag-specific (LTAg-specific) CD4+ T cells expressing up to 8 cytokines were also significantly enhanced in both IGRA+ and IGRA- vaccinees relative to unvaccinated controls, most markedly in IGRA+ vaccinees. A focused analysis of Th17 responses revealed expansion of Ag85A-, BCG-, and LTAg-specific total IL-17A+,IL-17F+,IL-22+, and IL-10+ CD4+ T cell effectors in both IGRA+ and IGRA- subjects. Also, innate IFN-γ+ NK/γδ/NKT cell responses were higher in both IGRA+ and IGRA- vaccinees compared with controls. This is the first evidence to our knowledge that BCG revaccination significantly boosts antimycobacterial Th1/Th17 responses in IGRA+ and IGRA- subjects.CONCLUSIONThese data show that BCG revaccination is immunogenic in IGRA- and IGRA+ subjects, implying that Mtb preinfection in IGRA+ subjects does not impact immunogenicity. This has implications for public health and vaccine development strategies.FUNDINGThis work was funded principally by DBT-NIH (BT/MB/Indo-US/HIPC/2013).

Risk Factors for False-Negative Interferon-γ Release Assay Results in Culture-Confirmed Childhood TB.

A negative interferon-γ release assay (IGRA) result might inappropriately lower the clinical suspicion for childhood tuberculosis (TB) and result in delayed treatment initiation. However, the risk factors associated with false-negative IGRA results in children remain unclear. Between May 2012 and January 2018, 156 culture-confirmed childhood TB patients who had received T-SPOT.TB test were included. Data, including demographic information and clinicopathological variables, were collected via questionnaires. Univariate and multivariate logistic regression analyses were performed to estimate the odds ratio (OR) and corresponding 95% CI of risk factors associated with false-negative T-SPOT.TB results. The positive rate of T-SPOT.TB test was 85.9% in childhood TB patients. Multivariate analysis revealed that younger age (≤ 9 years; OR = 4.782; 95% CI: 1.689, 13.539), weight for age (z-score > 0.37; OR = 4.256; 95% CI: 1.458, 12.428), and hypoproteinemia (total protein ≤ 68.4 g/L; OR = 7.131; 95% CI: 1.864, 27.271) were risk factors for false-negative T-SPOT.TB results in childhood TB. Younger age, overweight, and hypoproteinemia were found to be associated with false-negative T-SPOT.TB results in childhood TB. Health care professionals should consider these risk factors when evaluating suspected childhood TB with negative T-SPOT.TB results.

[Concordance between the test of the tuberculin and Interferon Gamma Release Assay-IGRA in patients with immune-mediated inflammatory diseases]. / Concordancia entre la prueba de la tuberculina y el Interferon Gamma Release Assay-IGRA en pacientes con enfermedades inflamatorias mediadas por la inmunidad.

OBJECTIVE: The immunosuppressive therapies in the treatment of the immune-mediated inflammatory diseases (EIMI) predispose individuals to the tuberculosis, so the screening of latent tuberculosis infection (ITL) and the treatment reduces the likelihood of a progression to an active tuberculosis. The aim of the study was to analyze the concordance between the test of the tuberculin (PT) and "Interferon Gamma Release Assay-IGRA" in relation to the type of EIMI and the immunosuppressive treatment (IS). METHODS: Transversal study of patients with EIMI candidates or in treatment IS forwarded to the ITL screening, from April 2017 until May 2018. The outcome variables were PT and IGRA. The explicative variables were: EIMI, IS, age, gender, prior BCG vaccination and tuberculosis risk factors. RESULTS: A total of 146 patients were analyzed (33[22.6%] vaccinated with BCG, 1 [0.7%] with a pre-diagnosis of tuberculosis, and 22 [15.1%] from an endemic country). Kappa index (k) was 0,338 between PT and IGRA for the whole sample. A lower concordance was found in patients with the Crohn's disease (k=0.125), in the ones treated with corticosteroids (k=0.222), vaccinated with BCG (k=0.122) and in patients from tuberculosis endemic countries (k=0.128). CONCLUSIONS: The concordance between PT and IGRA is affected in patients with EIMI, and to a greater extent to patients with the inflammatory bowel disease, with the corticotherapy, with the BCG vaccination, or in the ones from endemic countries.

Evaluation and treatment of latent tuberculosis infection among healthcare workers in Korea: A multicentre cohort analysis.

OBJECTIVE: Healthcare workers (HCWs) are one of the target groups for systematic testing and treatment of latent tuberculosis infection (LTBI) in a setting of low TB incidence. We performed this study to describe the testing of HCWs for LTBI and analyse the acceptance and completion of treatment of LTBI. METHODS: This retrospective cohort study was conducted in four university-affiliated hospitals between January 1 and December 31, 2018. HCWs with positive interferon-gamma release assay (IGRA) during LTBI screening were analysed. We assessed the acceptance and completion of LTBI treatment. RESULTS: Overall, 893 HCWs were IGRA positive. Among them, 609 HCWs visited the clinic for evaluation of LTBI. Of 609 HCWs who were evaluated, 302 (49.6%) were offered treatment for LTBI. The proportion of acceptance for treatment was 64.5% (195 of 302 HCWs). The treatment course was completed by 143 of 195 HCWs (73.3%). Three months of isoniazid and rifampin (3HR) was used in 137 HCWs (70.3%) and 4 months of rifampin (4R) in 58 (29.7%). 72 HCWs (36.9%) experienced at least one adverse drug events, but there was no different characteristics between completer and non-completer. CONCLUSION: The acceptance and completion of LTBI treatment were unsatisfactory. Subjective perspective regarding obstacles to treatment of LTBI needs to be explored to increase compliance to LTBI treatment.

High Rates of Indeterminate TB Tests Among Hospitalized Patients: Can We Optimize Use of Gamma Interferon Release Assays in Tuberculosis?

In the United States, high concern for iatrogenic reactivation to tuberculosis (TB) disease secondary to prescribed immunosuppression has resulted in increased use of the QuantiFERON-TB Gold In-Tube test (QFT-GIT) to screen for Mycobacterium tuberculosis (Mtb) infection. The aim of our study was to determine indications for QFT-GIT testing and risk factors for indeterminate QFT-GIT results. We retrospectively identified patients with QFT-GIT testing over a six-month period in a tertiary care academic health care system and performed a record review. Inpatients were 11 times more likely to have an indeterminate QFT-GIT result than outpatients (95% CI 7.6-16.2). 61.5% inpatient QFT-GITs were ordered during workup of active TB. Providers treating exogenously or endogenously immunosuppressed patients ordered the most QFT-GITs. We highlight the significant limitations of TB screening tests in the inpatient setting and the need to test earlier in those requiring immunosuppressive therapy to avoid indeterminate results.

Borderline-Positive Quantiferon in Children.

We systematically retested children with borderline-positive quantiferon (0.35-0.99 IU/mL) during the period 2015-2019. Among 647 tests, 27 (4%) were positive (>0.35 IU/mL). Borderline-positive quantiferon accounted for 10 of 27 (37%) positive tests. When retested, 9 of 10 (90%) were negative. Children younger than 5 years had negative tuberculin skin tests. Thus, we found high test variability in the borderline range and, in some children, high suspicion of false positive tests.