Diagnosis of latent Mycobacterium tuberculosis infection: tuberculin test versus interferon-gamma release

Abstract: INTRODUCTION: The treatment of individuals with active tuberculosis (TB) and the identification and treatment of latent tuberculosis infection (LTBI) contacts are the two most important strategies for the control of TB. The objective of this study was compare the performance of tuberculin skin testing (TST) with QuantiFERON-TB Gold In TUBE(r) in the diagnosis of LTBI in contacts of patients with active TB. METHODS: Cross-sectional analytical study with 60 contacts of patients with active pulmonary TB. A blood sample of each contact was taken for interferon-gamma release assay (IGRA) and subsequently performed the TST. A receiver operating characteristic curve was generated to assess the cutoff points and the sensitivity, predictive values, and accuracy were calculated. The agreement between IGRA and TST results was evaluated by Kappa coefficient. RESULTS: Here, 67.9% sensitivity, 84.4% specificity, 79.1% PPV, 75% NPV, and 76.7% accuracy were observed for the 5mm cutoff point. The prevalence of LTBI determined by TST and IGRA was 40% and 46.7%, respectively. CONCLUSIONS: Both QuantiFERON-TB Gold In TUBE(r) and TST showed good performance in LTBI diagnosis. The creation of specific diagnostic methods is necessary for the diagnosis of LTBI with higher sensitivity and specificity, preferably with low cost and not require a return visit for reading because with early treatment of latent forms can prevent active TB

Factors associated with tuberculosis retreatment in priority districts of Maranhão, Brazil

<p></p><p>Abstract This study investigated factors associated with cases of tuberculosis retreatment due to relapse and readmission after treatment abandonment. This is an analytical cross-sectional study type of cases reported in the Information System for Notifiable Diseases in priority municipalities in the State of Maranhão, from January 2005 to December 2010. A logistic regression model was used to identify the association. Patients aged between 40 and 59 years (OR = 1.49, p = 0.029) with a pulmonary clinical form (OR = 2.79, p = 0.016) were more likely to incur relapse. Readmissions after abandonment were more likely in males (OR = 1.53, p = 0.046), aged between 20 and 39 years (OR = 1.65, p = 0.007), with less than eight years of schooling (OR = 2.01, p = 0.037) and with alcohol dependence (OR=1.66, p = 0.037), which showed a higher probability of another abandonment (OR = 5.96, p < 0.001). These data reinforce the need for strategies aimed at this group, such as increased supervised treatment, intensified active search, post-discharge follow-up and health education action.</p><p></p