Tuberculin Test

INTRODUCTION Tuberculosis reactivation is one of significant complications after transplantation. Tuberculin skin test (TST) has been the major available screening test in end-stage renal disease patients, but it is associated with a low accuracy. Recently, an interferon-gamma release assay (IGRA) has been approved as a substitution test in diagnosis of Mycobacterium tuberculosis infection. This study aimed to compare the ability of the TST and IGRA in the diagnosis of latent tuberculosis in hemodialysis patients and investigate risk factors of having positive test results. MATERIALS AND METHODS Forty-seven hemodialysis patients underwent the IGRA and TST tests. Demographic data and blood samples were collected and chest radiography was done for all participants. RESULT Abnormal chest radiography was reported in 24% of the study group. The IGRA and TST were positive in 11 (23.4%) and 20 patients (43.5%), respectively. The agreement coefficient (kappa) between the IGRA and TST was 0....

Although the tuberculin skin test (TST) has been the mainstay of the diagnosis of latent tuberculosis infection (LTBI) for many decades, interferon-gamma release assays (IGRAs) are gaining acceptance and are more specific for this diagnosis. The characteristics of one such IGRA, the QuantiFERON-TB Gold Whole Blood In-Tube, make it feasible for use in a remote setting. This study performed 62 IGRAs with this test on individuals testing positive by TST, in a clinical setting over 3,000 km from the testing laboratory. Of these, 42 patients (68%) recorded negative results, 19 (31%) were positive, with only 1 result (2%) indeterminate. Negative, and therefore discordant in this study, test results were more common in those known to have been previously vaccinated with bacille Calmette-Guérin. These results are consistent with other reports, indicating that this approach to testing is logistically feasible, and has the potential to complement LTBI screening to assist tuberculosis control ...

This study shows a representative stratified cluster sample survey of the prevalence of comparative intradermal tuberculin test in cattle from four regions in Ethiopia. Using a cut-off for positivity of 2 mm, it assesses possible risk factors for tuberculin-positive reaction in cattle. Seventy-three villages in 24 kebeles (administrative units) were randomly selected, from which 2216 cattle from 780 owners were tested. In addition, 450 of these cattle owners were interviewed for risk factor assessment. Ninety-nine percent of the tested cattle in this rural livestock production system were traditional zebus. The individual overall prevalence of cattle bovine tuberculosis (BTB)e was 3%, with the highest found in Meskan Mareko, in Central Ethiopia (7.9%) and the lowest in Woldia, in the North East edge of the Rift Valley (1.2%). Generalised Linear Mixed Models (GLMM) with random effect on kebeles was used to analyse risk factors of cattle reactors and human tuberculosis (TB) infection....

In our study we evaluated the Quantiferon-TB Gold (QFT-G) test and compared it with tuberculin skin test (TST) positivity in 44 pulmonary and 21 extrapulmonary tuberculosis cases in whom active tuberculosis infection was suspected on clinical, microbiologic and radiologic grounds. QFT-G positivity was 75% in pulmonary tuberculosis and 76.2% in extrapulmonary tuberculosis. TST positivity was 68.2 and 62%, respectively. Although QFT-G positivity was higher than TST positivity, the difference was statistically insignificant (P=0.77). Similar to TST, QFT-G is one of the supplementary diagnostic tests for active tuberculosis disease and latent tuberculosis infection. Its advantage over TST is that it gives a result on the same day and it is unaffected by prior BCG and previous exposure to atypical mycobacteria. In conclusion, we think that, as with TST, a positive QFT-G result can be an adjunct to diagnosis in patients having clinical and radiological data compatible with tuberculosis.

We determined the prevalence of bovine tuberculosis in Jigawa State, northwestern Nigeria using the comparative intradermal tuberculin test in 22 herds consisting of 922 cattle with overall and individual prevalence of 1.08% (10/922) and 45.45% (10/22) obtained, respectively.

A 39-year-old woman was referred with a 1-year history of a 4-cm mass of the left axilla, compatible with a lymph node. Itchy red papules that evolved to crusty lesions and subsequently showed varioliform atrophic scarring appeared over the face, extensor surface of the arms, back, thighs, and scalp (Figs 1 and 2). Her history included weight loss of 8 kg, but no other associated symptoms or contact with tuberculosis patients. The blood count showed a normochromic–normocytic anemia with an erythrocyte sedimentation rate (ESR) slightly elevated at 28 mm in the first hour (normal, < 20 mm). Tuberculin skin test was positive (13 mm with necrotic reaction) and anti-human immunodeficiency virus serology was negative. Four lesional skin biopsies and one lymph node biopsy were performed and sent for histopathology and culture. The skin biopsy showed small-vessel lumen occlusion by tiny thrombi, endothelial hyperplasia, and intense perivascular inflammatory reaction throughout the dermis, together with partial degeneration of collagen, compatible with tuberculid. Lymph node biopsy showed chronic, necrotizing, granulomatous lymphadenitis, consistent with a diagnosis of lymph node tuberculosis. Mycobacteria were absent on Ziehl–Neelsen staining and culture in all specimens.Figure 1. Varioliform atrophic scarring over the extensor surface of the arms, typical of papulonecrotic tuberculid (PNT)Download figure to PowerPointFigure 1. Varioliform atrophic scarring over the extensor surface of the arms, typical of papulonecrotic tuberculid (PNT)Download figure to PowerPointFigure 2. Varioliform atrophic scarring over the back, typical of papulonecrotic tuberculid (PNT)Download figure to PowerPointFigure 2. Varioliform atrophic scarring over the back, typical of papulonecrotic tuberculid (PNT)Download figure to PowerPoint On the basis of the clinical features, positive tuberculin skin test, and histopathologic findings, a diagnosis of papulonecrotic tuberculid associated with tuberculous lymphadenitis was made. A triple therapeutic regimen with rifampicin, isoniazid, and pyrazinamide was started and the patient evolved with progressive clinical improvement. At the end of treatment at 6 months, there was clinical remission and improvement of anemia and ESR. Four months later, however, there was a clinical relapse of the lesions on the scalp, ultimately resulting in cicatricial alopecia with varioliform atrophic scarring (Figs 3 and 4). A biopsy of these new lesions was performed and showed focal necrosis (V-shaped) in the epidermis and dermis with follicular involvement and thrombotic occlusion of vessels, confirming the diagnosis of tuberculid. The patient was retreated with rifampicin, isoniazid, pyrazinamide, and ethambutol for 9 months. A new investigation of another internal focus of tuberculosis was negative.Figure 3. Cicatricial alopecia with varioliform atrophic scarring appearing after 6 months of treatment for tuberculosisDownload figure to PowerPointFigure 3. Cicatricial alopecia with varioliform atrophic scarring appearing after 6 months of treatment for tuberculosisDownload figure to PowerPointFigure 4. Cicatricial alopecia with varioliform atrophic scarring appearing after 6 months of treatment for tuberculosisDownload figure to PowerPointFigure 4. Cicatricial alopecia with varioliform atrophic scarring appearing after 6 months of treatment for tuberculosisDownload figure to PowerPoint In the last 2 years, the patient has had several recurring crops of lesions on the scalp. Further biopsies were taken, with histopathology showing nonspecific inflammatory changes. Cultures for Mycobacterium spp. were negative (five media: Lowenstein–Jensen, Lowenstein–Jensen supplemented with ferric ammonium citrate or pyruvate, Stonebrink and 7H9 supplemented with hemin) under different temperatures and light conditions. In addition, nucleic acid amplification for mycobacterial hsp65 using polymerase chain reaction restriction enzyme analysis methodology (Telenti A, Marchesi F, Balz M, et al. Rapid identification of mycobacteria to the species level by polymerase chain reaction and restriction enzyme analysis. J Clin Microbiol 1993; 31: 175–178; da Silva RA, Werneck Barreto AM, Dias Campos CE, et al. Novel allelic variants of mycobacteria isolated in Brazil as determined by PCR-restriction enzyme analysis of hsp65. J Clin Microbiol 2002; 40: 4191–4196) was negative. The patient is still being followed up in our clinic.

On May 2, 2005, a new in vitro test, QuantiFERON-TB Gold (QFT-G, Cellestis Limited, Carnegie, Victoria, Australia), received final approval from the U.S. Food and Drug Administration as an aid for diagnosing Mycobacterium tuberculosis infection. This test detects the release of interferon-gamma (IFN-g) in fresh heparinized whole blood from sensitized persons when it is incubated with mixtures of synthetic peptides representing two proteins present in M. tuberculosis: early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10). These antigens impart greater specificity than is possible with tests using purified protein derivative as the tuberculosis (TB) antigen. In direct comparisons, the sensitivity of QFT-G was statistically similar to that of the tuberculin skin test (TST) for detecting infection in persons with untreated culture-confirmed tuberculosis (TB). The performance of QFT-G in certain populations targeted by TB control programs in the United Stat...

In Taiwan, the tuberculin skin test (TST) is not recommended as a screening test for Mycobacterium tuberculosis (TB) infections. The aim of this study is to determine the prevalence and predictors of positive tuberculin reactivity and its association with TB infections among nursing home residents in Taiwan. A cross-sectional study and review of medical records were conducted at four nursing homes in Tainan City. A one-stage TST was performed by study nurses using two tuberculin units of purified protein derivative (PPD) of the RT23 strain. An induration ≥10 mm at 72 h was considered to be a positive reaction. Chest radiographs, acid-fast stains and mycobacterial cultures of three sputum samples were performed for those with a positive TST result. Of 115 residents (66.5% participation, mean age 73.1 years) who underwent a TST, 26 (22.6%) had a positive reaction. One woman was microbiologically diagnosed to have pulmonary TB. On multivariate analysis, a Bacille Calmette-Guérin (BCG) ...

Background: The aim of this study was to describe the clinical characteristics and potentially diagnostic specimens of pediatric patients with tuberculous pleural effusion (TPE) to make a prompt diagnosis.Methods: Children who had TPE from September 1997 to December 2003 were retrospectively reviewed at a tertiary pediatric facility in northern Taiwan.Results: There were seven boys and six girls and their ages ranged from 10 to 17 years (average, 14.6 years). Tuberculosis contact history was identified in only six patients (46%). Fever (12/92%), cough (9/69%) and malaise (6/46%) were the most common symptoms. Normal leukocyte count was found in 12 patients (92%). Chest radiograph review showed unilateral pleural effusion in 12 patients (92%) but parenchymal involvement was found in nine patients (69%). Most of the pleural fluid analysis showed a lymphocytic exudative effusion (5/6). The acid-fast bacilli (AFB) stain of sputum, gastric washing, and pleural aspirate was positive in six of 11 (55%), two of seven (29%), and one of five (20%) patients, respectively. Culture of sputum, gastric washing, and pleural aspirate yielded Mycobacterium tuberculosis in four of 11 (36%), two of seven (29%), and two of five (40%) patients, respectively. A total of 6 to 9 months of multiple-drug therapy for tuberculosis was successful without sequale.Conclusions: Tuberculous pleural effusion usually presents as an acute illness and should always be considered in the differential diagnosis for older children and adolescents with pneumonia. A normal leukocyte count with a lymphocytic exudative effusion may provide a clue to the correct diagnosis of TPE. Diagnostic specimen of sputum seems more effective and sensitive in childhood TPE, especially those having pulmonary involvement.

A possible relationship between Takayasu arteritis (TA) and tuberculosis (TB) has been suggested. An increased frequency of tuberculin skin test (TST) was observed in TA patients. Quantiferon-TB Gold test (QFT) is a new in vitro assay measuring interferon-gamma response to M. tuberculosis antigens and helpful in diagnosing latent TB infection. The aim of this study was to investigate latent TB infection among TA patients by the use of both TST and QFT Gold test. Ninety-four (male/female: 7/87) TA patients fulfilling ACR 1990 TA criteria from three different university hospitals in Turkey and 107 control subjects without inflammatory diseases were included in the study. Data about medical history (TA and TB) were collected for both groups. TST and QFT were performed. TST values ≥5 mm for TA patients and ≥15 mm for controls was accepted as TST positivity. Even though TA group was older (40 ± 12 vs. 32 ± 8, P P = 0.054). Although TST positivity was higher in TA group [55 patients (62.5%) vs. 24 controls (41.4%), P = 0.008], QFT positivity was similar between two groups [21 patients (22.3%) vs. 24 controls (22.4%), P > 0.05]. QFT was negative in two of six TA patients with previous TB history. Rate of latent TB infection in TA patients measured with QFT is no more than controls. QFT seems to be a good and favorable test compared with TST in detecting LTBI in TA.