QuantiFERON-TB Gold In-Tube Test Research Articles

Effect of CD4 count on Mycobacterium tuberculosis infection rates in people living with HIV: a comparative study in prison and community

To evaluate the impact of the CD4 count on ESAT6-CFP10 (EC) skin test, QuantiFERON-TB Gold In-tube test (QFT) and tuberculin skin test (TST) in a large prison and communities in Jiangsu Province among people living with HIV (PLHIV). Participants in communities were tested with the QFT and EC skin test and in prison were tested with the QFT, TST and EC skin test. A 4-knotted restricted cubic spline fitted for Logistic models was used to explore the cutoff point of CD4 count and the associations between changes in CD4 count and Mycobacterium tuberculosis (M.tb) infection. Among 1,815 PLHIV included, 19.3% (350) were from prisons and 80.7% (1465) were identified through community screenings. M.tb infection rates were 12.2% and 8.3% through QFT and EC tests, respectively. Odd Ratios (ORs) for infection increased with CD4 counts, peaking at 618 cells/mm3 for EC, 392 cells/mm3 for QFT, then plateaued. However, the pattern differed for EC between prison and screening scenarios. In prison settings, M.tb infection increased with CD4 count from 0 to 350 cells/mm3, plateaued until 500 cells/mm3, and then persistently increased. Conversely, for community, ORs decreased until 300 cells/mm3, followed by an increase between 300 and 729 cells/mm3, after which they continued to rise persistently. Our cross-sectional study among PLHIV revealed a higher rate of M.tb infection in prison compared to the community. The relationship between CD4 count and infection became negative after a certain threshold. This pivotal point differed with detection methods, with QFT showing lower CD4 thresholds than EC.

Evaluation of serial QuantiFERON-TB Gold in tube test results and tuberculosis infection status in patients with psoriasis receiving anti-IL-17 treatment (secukinumab and ixekizumab): Real-world data from a tuberculosis-endemic country.

In comparison with TNF-α inhibitors, anti-IL-17A agents are considered to have a lower risk of active tuberculosis (TB) or latent TB infection (LTBI) reactivation. In this study, we aimed to evaluate the TB infection status and serial QuantiFERON-TB-Gold in tube test (QFT) results of psoriasis patients using IL-17 inhibitors (secukinumab [SEC] and ixekizumab [IXE]) in a real-world setting from a tuberculosis-endemic country. Patients who used an anti-IL-17 agent for at least 3 months in our follow-up were included in the study. Patients' clinical and demographic features, baseline QFT results and latest QFT results (if any), and TB infection status were noted from the past medical records. A total of 717 patients, of whom 333 (46.4%) were female, were included in the study. The cumulative exposure time to an anti-IL-17 agent was 14,147 patient-months, 9743 patient-months for SEC and 4404 patient-months for IXE. Also, 459 (SEC = 305/IXE = 154) patients used an anti-IL-17 agent for ≥ 12 months. Of these, 125 had positive baseline QFT results. In all, 334 had negative baseline QFT results. The latest QFT result of 309 was also negative (persistent seronegative group). During follow-up, the QFT results of 10 patients changed from negative to positive (positive seroconversion group). Seven of them were using SEC and three were using IXE, respectively. No case of active TB infection was detected. In our study, the positive seroconversion rate of 10/334 seems high, but this did not translate to active disease. However, closer monitoring may be required, especially in patients with advanced age, the presence of PsA, long disease duration and long anti-IL-17 treatment duration.

Tuberculosis infection and hypertension: prevalence estimates from the US National Health and Nutrition Examination Survey

ObjectivesTuberculosis infection (TBI) is marked by dynamic host–pathogen interactions with persistent low-grade inflammation and is associated with increased risk of cardiovascular diseases (CVD) including acute coronary syndrome, myocardial infarction and...

Tuberculous peritonitis: an analysis of case series of 49 consecutive patients

Objectives: The incidence of tuberculous peritonitis has been reported between 0.1% and 0.7% among all tuberculosis types. This study, it was aimed to evaluate the cases with tuberculous peritonitis, which has an important place in the differential diagnosis of patients with ascites, clinically, biochemically, microbiologically, and histopathologically. Methods: : Forty-nine patients with a definite clinical, radiological, and histopathological diagnosis of tuberculous peritonitis, which formed the basis of our study, were analyzed retrospectively. Results: The mean age of patients with tuberculous peritonitis was found to be 39.45 ± 19.02 years. Purified-protein derivative (PPD) was positive in 23 (72%) of 32 patients with tuberculous peritonitis whose PPD results were recorded, in 9 (28%) PPD results were evaluated as anergic or negative. QuantiFERON-TB Gold In-Tube (QFT-GIT) test was sent in 10 of the patients, the result was positive in 9 (90%) patients and negative in 1 (10%) patient. There were 32 patients in whom tuberculosis polymerase chain reaction (PCR) was studied from ascitic fluid, 7 (22%) of the patients were PCR positive and 25 (78%) negative. Mycobacterium tuberculosis culture positivity was found in 18 (69%) of 26 patients who were biopsied. In total, 29 (59%) of the patients had M. tuberculosis culture positivity. Conclusions: Tuberculous peritonitis constitutes a public health problem in endemic regions of the world and tuberculous peritonitis should be considered in patients presenting with ascites. Despite all diagnostic difficulties, necessary tests, especially peritoneal biopsy, should be performed for early diagnosis, and it should not be forgotten that early initiation of treatment is very important in terms of morbidity and mortality of the disease.

Tuberculosis or Sarcoidosis or the Both? A Case Report of Concomitant Tuberculosis and Sarcoidosis

Tuberculosis and sarcoidosis are two chronic granulomatous diseases that are similar in many aspects, although different. We report a case of 38-year-old female patient who presented a progressive shortness of breath and recurrent epistaxis associated to a night sweats and fatigue with a deterioration of general condition, in which a CT-scan showed a multiple voluminous lymphadenopathy involving all the mediastinum territories, without parenchymal abnormalities. During investigations bronchoscopy showed mucosal hypertrophy and granulations located on the nasopharyngeal walls. The biopsy of the lip and nasal’s lesion showed a non-caseating granuloma and ACE (angiotensin converting enzyme) was high, which considered sufficient to retain the diagnosis of sarcoidosis, but the blood Quantiferon-TB Gold in Tube test was positive and the excision biopsy of cervical lymphadenopathy, revealed a necrotizing granulomatous inflammation suggestive of tuberculosis. The association between sarcoidosis and tuberculosis was discussed. the patient was treated with antituberculosis drugs during six months. The evolution was marked by a progressive regression of lymph nodes. There was no significant improvement of rhinological symptoms with local corticoids. Consequently, the corticosertoide treatement in form oral was introduced during 1 month. The prednisolone was gradually tapered off after 1 month due to the complete disappearance of lesions. The case described is suggestive of a coexistent systemic sarcoid manifestation and tuberculosis, which is an underrecognized entity in the medical literature.

Interferon-Gamma Release Assay Combined with Renal Indicators to Reduce the False-Negativity of Latent Tuberculosis Infection in End-Stage Renal Disease with Hemodialysis Patients.

Tuberculosis (TB) is still the main cause of mortality due to a single transfectant, Mycobacterium tuberculosis (MTB). Latent tuberculosis infection (LTBI) is a condition characterized by the presence of tuberculosis (TB) that is not clinically apparent but nonetheless shows a sustained response to MTB. Presently, tuberculin skin test (TST) and interferon gamma (IFN-γ) release assays (IGRAs) are mainly used to detect LTBI via cell-mediated immunity of T-cells. For people with end-stage renal disease (ESRD), the diagnosis of patients infected with MTB is difficult because of T-cell dysfunction. To get more accurate diagnosis results of LTBI, it must compensate for the deficiency of IGRA tests. Sixty-seven hemodialysis (HD) patients and 96 non-HD patients were enrolled in this study and the study population is continuously included. IFN-γ levels were measured by the QuantiFERON-TB Gold In-Tube (QFT-GIT) test. Kidney function indicators, blood urea nitrogen (BUN), serum creatinine (Cr), and estimated glomerular filtration rate (eGFR) were used to compensate for the declined IFN-γ levels in the IGRA test. In individuals who were previously undetected, the results of compensation with serum Cr increased by 10.81%, allowing for about 28% more detection, and compensation with eGFR increased by 5.41%, allowing for approximately 14% more detectable potential among them and employing both of them could enhance the prior shortcomings of IGRA tests. when both are used, the maximum compensation results show a sensitivity increase rate of 8.81%, and approximately 23% of patients who were previously undetectable may be found. Therefore, the renal function markers which are routine tests for HD patients to compensate for the deficiency of IGRA tests could increase the accuracy of LTBI diagnosis.

Psoriasis'te Biyolojik Tedavi Öncesi Latent Tüberküloz Enfeksiyonunun Değerlendirilmesi: Web Tabanlı Yorumlayıcı ile Yeni Bir Tanı Yaklaşımı

Purpose: The use of biological agents, particularly anti-TNF-alpha treatments, is associated with an elevated risk of tuberculosis (TB). Hence, a comprehensive assessment of latent tuberculosis infection (LTBI) before biologic therapies is imperative. The objective of this study was to evaluate the utility of an online tuberculin skin test (TST)/ interferon-γ release assay (IGRA) interpreter (OI-TST/IGRA) in assessing the risk of LTBI prior to initiating biological therapies in psoriasis patients.
 Materials and methods: 116 psoriasis patients who were previously evaluated for TB by a pulmonologist before being treated with a biologic agent were re-evaluated retrospectively with OI-TST/IGRA (tstin3d.com). Mean positive predictive value (PPV), mean annual risk of development of active tuberculosis (ARDATB), and mean cumulative risk of active tuberculosis (CRATB) values were calculated with OI-TST/IGRA and compared with previous results. Chi-square, Fisher-Freeman-Halton exact tests, Cohen's Kappa, and Mann-Whitney U-test were used in comparisons of groups. 
 Results: The PPV of the LTBI-positive group was significantly higher than the LTBI-negative group. The PPV, ARDATB and CRATB values of the TST size of >15 mm group were significantly higher than the TST size of 5-9 mm and TST size of 10-15 mm groups. The PPV, ARDATB, and CRATB values of the QuantiFERON-TB Gold In-tube test (QFT-GIT)-positive group were significantly higher than the QFT-GIT-negative group. And the same values of the chest X-ray (CXR)-positive group were significantly higher than the CXR-negative group. The PPV, ARDATB, and CRATB values were positively correlated with QFT-GIT and CXR results. In addition, the PPV was positively correlated with previous LTBI decisions and TSTs.
 Conclusion: OI-TST/IGRA in which many factors are questioned and PPV, ARDATB, and CRATB values are evaluated together, may be a valuable tool for assessing the risk of active TB in psoriasis patients and preventing overdiagnosis and unnecessary prophylaxis.

Exploration and improvement of QuantiFERON-TB assay in patients with indeterminate results in clinical practice: A head-to-head study

BackgroundWe implemented the QuantiFERON-TB Gold In-Tube (QFT-GIT) based on peripheral blood mononuclear cells (QFT-PBMCs) and QFT Gold Plus (QFT-Plus) in patients with indeterminate results, and use Mit-Nil value to identify false negatives and impaired cellular immunity. MethodsOne hundred seventy-one out of 2480 patients who had a QFT-GIT test were prospectively recruited and classified as high Nil (n = 35), low Mit (n = 75) and control (n = 61) cohorts. Head-to-head comparisons, i.e., QFT-PBMCs vs. QFT-GIT in high Nil cohort, QFT-Plus vs. QFT-GIT in low Mit cohort, and QFT-PBMCs vs. QFT-GIT in controls, were performed. Lymphocyte subsets counts were conducted in low Mit and control cohorts. ResultsA significant reduction of positive rate only occurred in Mit-Nil < 6 IU/ml (p < 0.001). QFT-PBMCs yielded 100 % valid results and had a significant Nil decline in high Nil cohort (0.98 ± 1.06 vs. 9.55 ± 0.64 IU/ml, p < 0.0001), while correlated well with QFT-GIT for qualitative (Cohen’s k = 0.93) and quantitative (TB–Ag [R2 = 0.91] and Mit [R2 = 0.94]) analyses. QFT-Plus produced 61.3 % valid results and had a significant Mit increase in low Mit cohort (0.82 ± 0.95 vs. 0.17 ± 0.11 IU/ml, p < 0.0001). Mit-Nil value significantly correlated with lymphocyte subsets counts (R:0.49–0.56, p < 0.0001), separately corresponding to thresholds of 4.26, 5.33, 5.55 and 5.81 IU/ml for predicting decreased total lymphocyte, T lymphocyte, CD4+ and CD8+ cells. ConclusionsQFT that replacing whole blood with PBMCs should be recommended to handle high Nil samples, and QFT-Plus can declined the frequency of low Mit results. In addition, Mit-Nil < 6 and 5.81 IU/ml are potential thresholds to identify the risk of false negatives and impaired cellular immunity, respectively.

P-472 Evaluation of the usefulness of the QuantiFERON-TB gold in-tube test for the detection of latent mycobacterium tuberculosis infections in patients underwent autologous stem cell transplantation

P-472 Evaluation of the usefulness of the QuantiFERON-TB gold in-tube test for the detection of latent mycobacterium tuberculosis infections in patients underwent autologous stem cell transplantation

Nomogram to determine predictive risk for active tuberculosis based on the QuantiFERON-TB Gold In-Tube test.

Interferon-γ release assay (IGRA) is a widely used blood test for detecting TB infection. However, a positive result of IGRA cannot differentiate active tuberculosis (ATB) infection from inactive tuberculosis (IATB). In this study, we established a nomogram model for predictive risk of ATB, differentiated from IATB, based on the concentration of interferon-γ (IFN-γ) of QuantiFERON-TB Gold In-Tube Test (QFT-GIT) and clinical characteristics. Participants with a positive QFT-GIT result were recruited and divided into a training and validation cohort according to hospitalisation date. The nomogram model for the differential diagnosis of ATB from IATB was established according to gender, age, pleural effusion (PE), and the concentration of IFN-γ in the Nil, TB antigen, and mitogen tube of QFT-GIT in the training cohort by logistic regression and validated in the validation cohort, and then combined with adenosine deaminase (ADA) to evaluated the performance value in ATB cases with PE. The area under receiver operating characteristic curve (AUC) of the diagnostic nomogram model, which we called the NSMC-ATB model for ATB diagnosis was 0.819 (95% CI 0.797-0.841), with sensitivity 73.16% and specificity 75.95% in training cohort, and AUC was 0.785 (95% CI 0.744-0.827), with sensitivity 67.44% and specificity 75.14% in validation cohort. A combination of the NSMC-ATB model and ADA performed better than the NSMC-ATB model and ADA alone in predicting ATB cases with PE, as AUC was 0.903 (95% CI 0.856-0.950) with sensitivity 78.63% and specificity 87.50%. We established an effective diagnostic nomogram model, called the NSMC-ATB model to differentiate ATB from IATB. Meanwhile, the combination of the NSMC-ATB model and ADA improved the performance value of ATB with PE.

Evaluation of ESAT6-CFP10 Skin Test for Mycobacterium tuberculosis Infection among Persons Living with HIV in China.

Recent global guidelines recommend Mycobacterium tuberculosis antigen-based skin tests, such as the ESAT6-CFP10 (EC) skin test, as acceptable alternatives to the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube test (QFT). However, the diagnostic value of these tests among persons living with HIV (PLHIV) is unknown. We aimed to assess the diagnostic accuracy of the EC among a cohort of PLHIV in China. We recruited PLHIV in Jiangsu Province, China, to assess sensitivity and specificity of the EC test. Participants were tested with the QFT, TST, and EC skin test. Results were stratified by age, M. tuberculosis BCG vaccination, and CD4 count. The sensitivity and specificity of the EC skin test was assessed using distinct cutoffs of the QFT and TST. Of 350 PLHIV enrolled in the study, 58 (16.6%), 89 (25.4%), and 59 (16.9%) tested positive with the EC test, the QFT, and the TST, respectively. Positivity increased with CD4 count; however, these trends were similar across tests. At a 5-mm cutoff, EC skin test specificity was high (99.6%, 95% confidence interval [CI] 95% CI = 97.7 to 100.0); however, sensitivity was moderate (81.4%; 95% CI = 66.6 to 91.6). After stratifying by BCG, the sensitivity and specificity were 86.4% (95% CI = 65.1 to 97.1) and 99.1% (95% CI = 95.0 to 100.0) among vaccinated PLHIV and 76.2% (95% CI = 52.8 to 91.8) and 100.0% (95% CI = 97.2 to 100.0) among unvaccinated PLHIV, respectively. Among PLHIV, the diagnostic value of the EC skin test remained high, regardless of BCG vaccination or CD4 count. The EC skin test performed comparably to TST and may be a valid alternative diagnostic test to use in settings or populations with high HIV prevalence and BCG vaccination. To our knowledge, this is the first study to evaluate the novel ESAT6-CFP10 skin test among PLHIV. Among 350 PLHIV, the test displayed high specificity and sensitivity, a finding which did not markedly differ based on BCG vaccination and CD4 count.

Comparing the diagnostic performance of QuantiFERON-TB Gold Plus with QFT-GIT, T-SPOT.TB and TST: a systematic review and meta-analysis

BackgroundQuantiFERON-TB Gold Plus (QFT-Plus) is an important test that has emerged in recent years for detecting TB infection. We conducted a review to compare the sensitivity, specificity and positive rate of QFT-Plus with that of QuantiFERON-TB Gold In-Tube (QFT-GIT), T-cell spot of tuberculosis assay (T-SPOT.TB) and Tuberculin test (TST).MethodsPubMed and Embase were searched, without language restrictions, from 1 January 2015 to 31 March 2022 using “Mycobacterium tuberculosis Infections” and “QuantiFERON-TB-Plus” as search phrases. We estimated the sensitivity from studies of patients with active tuberculosis, specificity from studies of populations with very low risk of TB exposure, and positive rate from studies of high-risk populations. The methodological quality of the eligible studies was assessed, and a random-effects model meta-analysis was used to determine the risk difference (RD). We assessed the pooled rate by using a random-effects model. This study was registered in PROSPERO (CRD 42021267432).ResultsOf 3996 studies, 83 were eligible for full-text screening and 41 were included in the meta-analysis. In patients with active TB, the sensitivity of QFT-Plus was compared to that of QFT-GIT and T-SPOT.TB, respectively, and no statistically differences were found. In populations with a very low risk of TB exposure, the specificity of QFT-Plus was compared with that of QFT-GTI and T-SPOT.TB, respectively, and no statistically differences were found. Two studies were eligible to compare the specificity of the QFT-Plus test with that of the TST test, and the pooled RD was 0.12 (95% CI 0.02 to 0.22). In high-risk populations, 18 studies were eligible to compare the positive rate of the QFT-Plus test with that of the QFT-GIT test, and the pooled RD was 0.02 (95% CI 0.01 to 0.03). The positive rate of QFT-Plus was compared with that of T-SPOT.TB and TST groups, and no statistically differences were found.ConclusionsThe diagnostic performance of QFT-Plus was similar to that of QFT-GIT and T-SPOT.TB, but was slightly more specific than TST.

Predictors for False-Negative Interferon-Gamma Release Assay Results in Hemodialysis Patients with Latent Tuberculosis Infection.

The present study aimed to clinically evaluate the effect of T-cell dysfunction in hemodialysis (HD) patients with latent tuberculosis (TB) infection (LTBI) who were false-negatives in the QuantiFERON-TB Gold In-Tube (QFT-GIT) test. Whole blood samples from a total of 20 active TB patients, 83 HD patients, and 52 healthy individuals were collected, and the QFT-GIT test was used for measuring Mycobacterium tuberculosis (MTB)-specific interferon gamma (IFN-γ) level. The positive rate of the IFN-γ release assays (IGRAs) in HD patients was lower than the negative rate. The mean value of MTB-specific IFN-γ level, which determines the positive rate of the IGRA test, was highest in active TB, followed by HD patients and healthy individuals. Among HD patients, phytohemagglutinin A (PHA)-stimulated IFN-γ levels of approximately 40% were 10.00 IU/mL or less. However, there was no low level of PHA-stimulated IFN-γ in the healthy individuals. This reveals that T-cell function in HD patients was reduced compared to healthy individuals, which leads to the possibility that QFT-GIT results in HD patients are false-negative. The clinical manifestations of TB in patients on HD are quite non-specific, making timely diagnosis difficult and delaying the initiation of curative treatment, delay being a major determinant of outcome.

Determinants of latent tuberculosis infection and treatment interruption in long-term care facilities: A retrospective cohort study in Taiwan.

Latent tuberculosis infection (LTBI) treatment is challenging in long-term care facilities (LTCFs) residents due to the occurrence of medical complexities. However, factors associated with treatment interruption have not been extensively studied. This retrospective cohort study aimed to determine LTBI-associated factors and treatment interruption in LTCF residents and employees in Taiwan. From May 2017 through September 2020, the residents and employees of 20 LTCFs in Taipei, Taiwan, were screened for LTBI by using QuantiFERON-TB Gold In-Tube test. The LTBI individuals underwent directly observed preventive therapy (DOPT), including regimens of 9-month daily isoniazid (9H) and 3-month weekly isoniazid plus rifapentine (3HP). All the LTBI cases were followed up till treatment completion, death, or treatment interruption. Among 2207 LTCF subjects, 16.8% had LTBI. After controlling for other covariates, residents of public facilities had a significantly higher LTBI prevalence than those of private facilities (adjusted odds ratio [AOR]=1.43; 95% confidence interval [CI]: 1.08-1.88). Among 264 LTBI cases receiving preventive therapy, 52 (19.7%) had treatment interruption. LTBI cases receiving 3HP were less likely to have treatment interruption than those receiving 9H (AOR=0.22; 95% CI: 0.07-0.71). LTCF residents, particular those living in public facilities, had a high LTBI prevalence. 3HP with DOPT is considered the priority regimen for preventive therapy among LTBI cases in LTCFs.

Performance of LTBI Screening in Patients with Rheumatic Diseases Using Two Different Interferon-Gamma Releasing Assays.

To evaluate the concordance between QuantiFERON-TB Gold in-tube test (QFT-GIT) and T-SPOT.TB test (T-SPOT) for the screening of latent tuberculosis infection (LTBI) in patients with rheumatic diseases (RDs). Patients diagnosed as rheumatic diseases (RDs) with clinical indications for test of interferon gamma release test (IGRA) were prospectively recruited from 2019 to 2020. The consistency of QFT-GIT and T-SPOT was assessed by Kappa analysis and the factors associated with the indeterminate results were explored by multivariable logistic analysis. A total of 108 patients with RDs were enrolled, including 64 patients with systemic lupus erythematosus (SLE) and 44 with inflammatory arthritis (26 with rheumatoid arthritis (RA) and 18 with ankylosing spondylitis (AS)). Poor concordance was confirmed between QFT-GIT and T-SPOT results in patients with SLE (K = 0.175, 95% confidence interval [95% CI] [-0.06, 0.40], p < 0.001), whereas concordance was moderate in patients with inflammatory arthritis (K = 0.539, 95% CI [0.11, 0.88], p < 0.001). Among SLE patients, the ratio of indeterminate results in detecting LTBI was significantly higher by QFT-GIT than by T-SPOT (18.8% vs. 4.7%, p = 0.013), while the statistical difference was not achieved in patients with inflammatory arthritis. The multivariable logistic analysis identified that the presence of lower lymphocyte counts (odds ratio [OR] = 0.81, 95% CI [0.68, 0.97], p = 0.020) was the independent predictor of an indeterminate result of the QFT-GIT in SLE patients. In patients with RDs, the result of screening of LTBI was more definitive by T-SPOT test than QFT, and the concordance was poor especially in the setting of SLE.

Factors Influencing False-Negative Results of QuantiFERON-TB Gold In-Tube (QFT-GIT) in Active Tuberculosis and the Desirability of Resetting Cutoffs for Different Populations: A Retrospective Study.

Objectives The value of QuantiFERON-TB Gold In-Tube (QFT-GIT) in the diagnosis of TB varies by population, comorbidities, and other factors. In this study, we aimed to investigate factors that influence false-negative results of QFT-GIT test in the diagnosis of TB as well as the impact of different cutoffs on the diagnostic value. Methods A total of 3562 patients who underwent QFT-GIT tests at Shanghai Pulmonary Hospital were enrolled retrospectively between May 2016 and May 2017. False-negative and false-positive results were analyzed using different clinical stratifications. The optimal cutoff values were established under different clinical conditions. Results Positive QFT-GIT results greatly shortened the time taken to diagnose smear-negative TB. The factors of age, smear and culture results, site of TB, comorbidity with tumors, white blood cell count, neutrophil count, and CD4/CD8 ratio were significantly correlated with false-negative QFT-GIT results (p < 0.05). Personalized cutoff values were established according to different influencing factors. The results showed high consistency between the smear-negative and total populations. Conclusion QFT-GIT can facilitate the early diagnosis of smear-negative TB. The diagnostic performance of the QFT-GIT test in the diagnosis of active TB was shown to be affected by many clinical factors. Personalized cutoff values may have superior value in the identification of active tuberculosis under different conditions.

Analysis of the diagnostic efficacy of the QuantiFERON-TB Gold In-Tube assay for preoperative differential diagnosis of spinal tuberculosis.

BackgroundDifferential diagnosis of spinal tuberculosis is important for the clinical management of patients, especially in populations with spinal bone destruction. There are few effective tools for preoperative differential diagnosis in these populations. The QuantiFERON-TB Gold In-Tube (QFT-GIT) test has good sensitivity and specificity for the diagnosis of tuberculosis, but its efficacy in preoperative diagnosis of spinal tuberculosis has rarely been investigated.MethodA total of 123 consecutive patients with suspected spinal tuberculosis hospitalized from March 20, 2020, to April 10, 2022, were included, and the QFT-GIT test was performed on each patient. We retrospectively collected clinical data from these patients. A receiver operating characteristic (ROC) curve was plotted with the TB Ag-Nil values. The cutoff point was calculated from the ROC curve of 61 patients in the study cohort, and the diagnostic validity of the cutoff point was verified in a new cohort of 62 patients. The correlations between TB Ag-Nil values and other clinical characteristics of the patients were analyzed.ResultsOf the 123 patients included in the study, 51 had confirmed tuberculosis, and 72 had non-tuberculosis disease (AUC=0.866, 95% CI: 0.798-0.933, P<0.0001). In patients with spinal tuberculosis, the QFT-GIT test sensitivity was 92.16% (95% CI: 80.25%-97.46%), and the specificity was 67.14% (95% CI: 54.77%-77.62%). The accuracy of diagnostic tests in the validation cohort increased from 77.42% to 80.65% when a new cutoff point was selected (1.58 IU/mL) from the ROC curve of the study cohort. The TB Ag-Nil values in tuberculosis patients were correlated with the duration of the patients’ disease (r=0.4148, P=0.0025).ConclusionThe QFT-GIT test is an important test for preoperative differential diagnosis of spinal tuberculosis with high sensitivity but low specificity. The diagnostic efficacy of the QFT-GIT test can be significantly improved via application of a new threshold (1.58 IU/mL), and the intensity of the QFT-GIT test findings in spinal tuberculosis may be related to the duration of a patient’s disease.

Screening of latent tuberculosis infection among patients with diabetes mellitus from a high-burden area in Brazil.

Although several cohort studies have raised the important association between diabetes mellitus (DM) and latent tuberculosis infection (LTBI), evidences are limited and controversial. Furthermore, it is well documented that the poor glycemic control may exacerbate the risk for active TB. Thus, the monitoring of diabetic patients living in high-incidence areas for TB is an important concern in views of available diagnostic tests for LTBI. In this cross-sectional study, we estimate the association of DM and LTBI among diabetic patients classified as type-1 DM (T1D) or type-2 DM (T2D) living in Rio de Janeiro, RJ, Brazil - considered a high TB burden region of these country. Non-DM volunteers were included as endemic area healthy controls. All participants were screened for DM using glycosylated-hemoglobin (HbA1c) and for LTBI using the QuantiFERON-TB Gold in Tube (QFT-GIT). Demographic, socioeconomic, clinical and laboratorial data were also assessed. Among 553 included participants, 88 (15.9%) had QFT-GIT positive test, of which 18 (20.5%) were non-DM, 30 (34.1%) T1D and 40 (45.4%) T2D. After adjustments for potential baseline confounders, age, self-reported non-white skin color and an active TB case in the family were significantly associated with LTBI among the studied population by using a hierarchical multivariate logistic regression analysis. Additionally, we verified that T2D patients were able to produce significant increased interferon-gamma (IFN-γ) plasma levels in response to Mycobacterium tuberculosis-specific antigens, when compared to non-DM individuals. Altogether, our data showed an increased prevalence of LTBI among DM patients, albeit non-statistically significant, and point out to important independent factors associated with LTBI, which deserve attention in monitoring patients with DM. Moreover, QFT-GIT test seems to be a good tool to screening LTBI in this population, even in a high TB burden area.

Interferon-Inducible Protein-10 as a Marker to Detect Latent Tuberculosis Infection in Patients with Inflammatory Rheumatic Diseases.

It is important to identify cases of latent tuberculosis infection (LTBI) who are at risk for tuberculosis (TB) reactivation. We aimed to evaluate the performance of interferon (IFN)-gamma-inducible protein 10 (IP-10) as a marker to detect LTBI in patients with inflammatory rheumatic diseases (IRD). This study comprised 76 consecutive subjects with IRD. Patients with a history of TB or having active TB were excluded. In all patients, IP-10 level was measured and tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube test (QFT-GIT) were performed. Seventy patients with complete test results were analyzed. Twenty-one (30%) QFT-GIT-positive patients were defined as having LTBI. IP-10 yielded 2197 pg/mL cut-off point. At this cut-off point, IP-10 showed 89% specificity with a sensitivity of 91% (AUC: 0.950, 95% CI 0.906–0.994). TST, QFT-GIT, and IP-10 were positive in 77.1%, 30%, and 44.3% of the patients, respectively. Concordance among the results of TST, QFT-GIT, and IP-10 tests was evaluated. Agreement was poor between IP-10 and TST (58.6%, κ = 0.19), whereas it was good between QFT-GIT and IP-10 (84.3%, κ = 0.65). The results of the present study demonstrated that sensitivity and specificity of released IP-10 were as high as those of QFT-GIT in indicating LTBI in IRD patient group.

A prevalence study in Guadalajara, Mexico, comparing tuberculin skin test and QuantiFERON-TB Gold In-Tube.

Tuberculosis (TB) is a prevalent disease throughout the world. The extent of TB illness in childhood is not clear; recent data shows that 10-20% of the cases are found in children under 15 years old. In 2017, 1 million children developed the disease, of which 9% were co-infected with HIV. A cross-sectional study that analyzed 48 children diagnosed with HIV-infection in Guadalajara, Mexico. The tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube test (QFT) were performed and compared to diagnose latent TB infection (LTBI). The average age was 9 years old (± 4), with an age range of 1-16 years; the 6-12-year-old group predominated with 50% of cases. 27 patients (56%) were male; 83% had received the BCG vaccination and 23% had a history of being contacts of TB cases. In the study, 40 patients (83%) were without immunosuppression; seven (15%) with moderate immunosuppression, and only one patient had severe immunodeficiency. Overall, 3 of the 48 children (6.2%) had a positive TST, while 8 out of 48 (16.6%) had a positive QFT. The concordance between the two tests was 89.6% (43/48) with Kappa = 0.5 (95% CI, 0.14-0.85). The QFT test represents an opportunity in the diagnosis of LTBI, particularly in pediatric HIV- patients. This is the first study that compares the two tests (TST and QFT) in children with HIV-infection in Guadalajara, Mexico.