Interferon-Gamma Release Assays for the diagnosis of Extrapulmonary Tuberculosis: A Systematic Review and Meta-Analysis.

FEMS Immunol Med Microbiol. 2012 Apr 9;

Authors: Fan L, Chen Z, Hao XH, Hu ZY, Xiao HP

Abstract
Interferon-gamma release assays (IGRAs) are a new diagnostic method for Mycobacterium TB infection. However, diagnostic value of IGRAs for extrapulmonary TB (EPTB) has not been clarified. We searched several databases and selected papers with strict included criteria, evaluated the evidence of commercially available IGRAs(QuantiFERON(®) -TB Gold QFT-G or QFT-GIT and T-SPOT(®) .TB) on blood and TST using random effects models. 20 studies with 1711 patients were included. After excluding the indeterminate results, the pooled sensitivity for the diagnosis of EPTB was 72% (95% CI, 65-79%) for QFT-G or GIT and 90% (95%CI, 86-93%) for T-SPOT, the sensitivity of QFT-G or GIT in high-income countries (79%,95%CI 72-86%) was much higher than that(29%, 95%CI, 14-48%) in low/middle-income countries. The pooled specificity for EPTB was 82% (95% CI, 78-87%) for QFT-G or GIT and 68% (95%CI, 64-73%) for T-SPOT. The pooled sensitivity of TST from 4 studies in high-income countries was lower than that of IGRAs. T-SPOT is more sensitive to detect EPTB than QFT-G or GIT and TST. However, both IGRAs and TST have similar specificity for EPTB. IGRAs have limited value to screen and rule out EPTB as diagnostic tool, especially in low/middle-income countries. Immunosuppressive condition of patients can not affect diagnostic accuracy of IGRAs for EPTB. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

PMID: 22487051 [PubMed - as supplied by publisher]

Tuberculosis diagnostics and biomarkers: needs, challenges, recent advances, and opportunities.

J Infect Dis. 2012 May;205 Suppl 2:S147-58

Authors: McNerney R, Maeurer M, Abubakar I, Marais B, McHugh TD, Ford N, Weyer K, Lawn S, Grobusch MP, Memish Z, Squire SB, Pantaleo G, Chakaya J, Casenghi M, Migliori GB, Mwaba P, Zijenah L, Hoelscher M, Cox H, Swaminathan S, Kim PS, Schito M, Harari A, Bates M, Schwank S, O'Grady J, Pletschette M, Ditui L, Atun R, Zumla A

Abstract
Tuberculosis is unique among the major infectious diseases in that it lacks accurate rapid point-of-care diagnostic tests. Failure to control the spread of tuberculosis is largely due to our inability to detect and treat all infectious cases of pulmonary tuberculosis in a timely fashion, allowing continued Mycobacterium tuberculosis transmission within communities. Currently recommended gold-standard diagnostic tests for tuberculosis are laboratory based, and multiple investigations may be necessary over a period of weeks or months before a diagnosis is made. Several new diagnostic tests have recently become available for detecting active tuberculosis disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. In the absence of effective prevention strategies, high rates of early case detection and subsequent cure are required for global tuberculosis control. Early case detection is dependent on test accuracy, accessibility, cost, and complexity, but also depends on the political will and funder investment to deliver optimal, sustainable care to those worst affected by the tuberculosis and human immunodeficiency virus epidemics. This review highlights unanswered questions, challenges, recent advances, unresolved operational and technical issues, needs, and opportunities related to tuberculosis diagnostics.

PMID: 22496353 [PubMed - in process]

Diagnostic yield of post-bronchoscopy sputum smear in pulmonary tuberculosis.

Scand J Infect Dis. 2012 May;44(5):369-73

Authors: Malekmohammad M, Marjani M, Tabarsi P, Baghaei P, Sadr Z, Naghan PA, Mansouri D, Masjedi MR, Velayati AA

Abstract
Abstract Background: The early definitive diagnosis of pulmonary tuberculosis (TB) is important for control of the disease in the community. We performed this study to evaluate the additional gain of post-bronchoscopy sputum in the diagnosis of pulmonary TB. Methods: Bronchoscopy and bronchoalveolar lavage were performed for 126 patients suspected of pulmonary TB who either had 3 negative sputum smears for acid-fast bacilli or could not expectorate. After bronchoscopy the patients were asked to give sputum samples for 3 consecutive days. All of the obtained specimens were investigated for Mycobacterium tuberculosis by smear and culture. Results: Pulmonary TB was confirmed in 56 patients. Among all confirmed cases, the sensitivity of bronchoalveolar lavage smear was 57.1% (32 of 56), sensitivity of post-bronchoscopy smear was 76.7% (43 of 56), and the yield of a combination of the 2 methods was 83.9% (47 of 56). Results of post-bronchoscopy sputum smears were not significantly related to sex, age, human immunodeficiency virus (HIV) infection, presence of cavitary lesions on chest X-ray, or the ability to expectorate before bronchoscopy (p > 0.05). Conclusion: Evaluation of post-bronchoscopy sputum smears is helpful for earlier diagnosis of pulmonary TB and is an inexpensive and accessible assay.

PMID: 22497518 [PubMed - in process]

OBJECTIVE: 1) To evaluate the tuberculosis (TB) related financial burden of patients and health care providers over the course of diagnosis and treatment by choice of directly observed treatment (DOT); and 2) to examine treatment outcomes for different DOT programmes in Cambodia.

SETTING AND DESIGN: Subjects were patients diagnosed with smear-positive pulmonary TB between July 2008 and January 2009 at 17 health facilities providing multiple DOT programmes. Treatment outcomes for the different DOT programmes as well as direct and indirect household costs and medical delivery costs for the treatment and care of 277 patients were examined.

RESULTS: Per patient costs of anti-tuberculosis treatment for patients with non-multidrug-resistant TB who did not have human immunodeficiency virus co-infection ranged from a high of US$1900 for in-patient DOT to a low of $395 for DOT provided at home. All costs among patients treated with hospital DOT were consistently higher than for those treated with non-hospital DOT. The percentage of treatment success was not significantly different between hospital and non-hospital DOT programmes (all >89%).

CONCLUSION: Non-hospital DOT programmes ease the financial burden on both patients and health care providers, while resulting in treatment success rates similar to those of hospital DOT.