Evaluation of sensitivity and specificity of tuberculosis diagnostic tools among HIV positive patients: A cross-sectional study

Background and Objective: Tuberculosis is the major cause of morbidity and mortality among HIV patients. Thus, early diagnosis of Tuberculosis among these patients is important. The purpose of then present study was to determine the Sensitivity, Specificity, PPV and NPV for tools of diagnosing TB among HIV patients referred to behavioral disorder counseling center of Shiraz city.Materials and Methods: In this cross sectional study, ۲۵۰ HIV+ patients in Shiraz were evaluated. For each patient, three sputum smears and a Chest X-ray and PPD was taken.Sensitivity, specificity, and positive and negative predictive values were determined based on the results of sputum cultures as a gold standard.Results: Among ۲۵۰ HIV+ individuals who entered the study, ۸ (۳.۲ %) were diagnosed with tuberculosis. The sensitivity, specificity, PPV and NPV for chest x-ray were ۶۲.۵%, ۹۶%, ۳۸% and ۹۸.۷%, respectively. Also they were ۶۲.۵%, ۹۸.۷%, ۶۲.۵% and ۹۸.۷% for AFB ۱, and ۲۵%, ۹۹.۵%, ۶۶% and ۹۷.۵% for AFB ۲. Finally, these factors were ۹۹.۵%, ۹۹.۵%, ۶۶% and ۹۷.۵% for AFB ۳.Conclusion: The prevalence of TB among HIV+ patients referring to the behavioral disease counseling center in Shiraz was lower than in other endemic areas of developing countries. The screening tools for diagnosis of tuberculosis included the chest x-ray and Acid Fast Bacilli and PPD test in order to find out the important role of detecting TB disease among HIVinfected people.

Keywords:

Co-infection , HIV/AIDS , Sputum culture , Sputum smear , Tuberculosis