Objective: To evaluate the competence of senior medical students in diagnosing tuberculosis (TB) based on their reading of chest X-rays, as well as to identify the factors associated with high scores for the overall interpretation of chest X-rays. Methods: In October 2008, a convenience sample of senior medical students who had undergone formal training in radiology at the Federal University of Rio de Janeiro School of Medicine, in the city of Rio de Janeiro, Brazil, were invited to participate in the study. Six chest X-rays (three of TB patients and three of patients without TB) were selected. Participants were asked to choose one of the three probable radiological interpretations, and one of the four subsequent suitable clinical approaches. They also completed a questionnaire designed to collect data related to demographics, career of interest, time spent in emergency rooms and year of study. The sensitivity and specificity related to competence in the radiological diagnosis of TB, as well as a score for the overall interpretation of chest X-rays, were calculated. Results: The sensitivity of the probable radiological diagnosis of pulmonary TB, based on the three chest X-rays of patients with TB (minimal, moderate and extensive) was 86.5%, 90.4% and 94.2%, respectively, and the specificity was 90%, 82% and 42%. The only factor associated with a high score for the overall radiological interpretation was the year of study. Conclusions: In this sample of medical students, who had received formal training in radiology early in their medical school course, the competence in interpreting the chest X-rays of TB patients was good. The year of study seems to influence overall chest X-ray reading skill.

Keywords: Tuberculosis, pulmonary; Radiology; Education, medical.

Introduction: There have been few Latin American studies investigating the fact that the rate of tuberculosis (TB) infection among medical students is higher than the 1.3% rate seen in the population at large. Objective: To describe the cumulative incidence and the relative risk for TB infection among medical students. Method: In 1998, a prospective cohort study was conducted involving medical students at the Universidade Federal do Rio de Janeiro Faculdade de Medicina who tested negative (induration <10 mm) on the tuberculin skin test (TST). Students were tested using the two-step TST method and were retested one year later. The students tested were at two different stages in their training: pre-clinical (no contact with patients) and final year (contact with patients). Information about demographic characteristics, BCG vaccination history, and instances of potential exposure to Mycobacterium tuberculosis were obtained using a standardized questionnaire. Of the 575 students initially enrolled, 72% (414) completed the study. Results: The TSTs of 16 (3.9%) of the 414 students converted, representing a cumulative incidence of 3.9% (95% confidence interval = 1.06 to 12.1). Senior medical students were at an almost fourfold higher risk for M. tuberculosis infection than were those in pre-clinical training. Conclusion: The risk for TST conversion is very high in this population.

Keywords: PPD. Tuberculosis-infection. Tuberculin conversion. Medical students

Introduction: The teaching hospital, HUCFF, Southeastern Brazil, annually receives three hundred tuberculosis cases. Medical students have their practice at that hospital. Objective: To determine the prevalence of Mycobacterium tuberculosis (Mtb) infection among the students of the UFRJ School of Medicine. Design: Cross-sectional study of medical students at different levels of their training programs. Information about social and demographic characteristics, BCG vaccination history, and potential exposures to tuberculosis were obtained with a standardized questionnaire. Tuberculin skin testing was used to determine the prevalence of tuberculosis infection. Results: The prevalence of tuberculin skin testing positivity among medical students increased as they advanced to higher training levels (4.6%, 7.8%, 16.2%, respectively; P = 0.002). The risks were greatest during the years of clinical training, when medical students had more contact with patients. Conclusions: Medical students in the HUCFF/UFRJ may be at an increased risk of M. tuberculosis infection. A program of routine tuberculin skin testing, combined with interventions to confirm TST conversion and to reduce the risk of nosocomial transmission in the workplace is needed.

Keywords: Nosocomial infection. Medical students. Risk factors. Cross-sectional studies.