Determining the diagnostic value of mycobacterium tuberculosis DNA in the differentiation of blood samples of patients with active pulmonary tuberculosis and healthy controls using polymerase chain reaction

Tuberculosis [TB] is now a major cause of mortality and morbidity in the world. Nowadays, different methods are used to diagnose tuberculosis. Although classical microbiological methods [such as sputum smear] are specific, they have little sensitivity and the culture is also time-consuming. Using Polymerase Chain Reaction [PCR] in blood samples in terms of Mycobacterium tuberculosis DNA, this study examines diagnostic power of this test in the diagnosis of pulmonary tuberculosis compared with other standard methods. In a cross-sectional descriptive-analytic study, blood samples were taken from 40 TB patients and 40 non-TB cases. Following DNA extraction by the commercial kit QIAGEN, the PCR assay was performed using IS6110 primer. In this study, there were 80 people in two groups of TB and non-TB cases. Each group composed of 14 men [35%] and 26 women [65%]. Sensitivity, specificity as well as positive and negative predictive values obtained 37.5, 100, 100 and 61.5%, respectively. Despite high costs of using PCR for TB diagnosis, sensitivity of this method is low due to various factors and cannot replace current standard methods for TB diagnosis such as smear and culture. It can only be used as a complementary method to confirm diagnosis in strongly suspected cases of tuberculosis

causes anthracofibrosis? either tuberculosis or smoke

To define the prevalence of anthracofibrosis in fibreoptic bronchoscopy of highly suspected patients who were likely to have pulmonary tuberculosis but they had three times negative sputum exams for acid-fast bacilli and to determine the association of anthracofibrosis with tuberculosis and prolonged smoke exposure. The fibreoptic bronchoscopy was done in 207 patients; 106 male and 101 female their age was from 15 to 91 years and most of them were referred by the professors of infectious diseases. Exact medical history was taken and specially focused on the past medical history of tuberculosis and chronic exposure to any kind of smoke. Then they were divided into two groups, with or without anthracofibrosis, and then this data was analyzed among the two groups. Anthracofibrosis was diagnosed in 34 cases [19 female, 15 male]. Past medical history of pulmonary tuberculosis was positive in 45 patients [26 males and 19 females] and Seventy one patients [38 female, 33 male] had positive history of prolonged exposure to smoke but, the most common cause of smoke exposure in females was the cooking of bread in the traditional clay oven [92 percent] and smoking in males [96 percent]. The finding of this study suggests that the incidence of active or old tuberculous infection was significantly higher in anthracofibrosis group in males as well as females. Although prolonged smoke exposure was significantly higher in anthracofibrosis group but, this relationship was just true in females