RESUMO
Decision analysis was used to examine the potential effect on cost and expected quality of care of the introduction of serodiagnosis by enzyme-linked immunosorbent assay (ELISA) of tuberculosis at the Instituto de Torax in La Paz, Bolivia. Previously published data collected at that facility were used as the basis for this analysis. Decision trees were constructed including test availability, test result, test predictive values, and the consequences of correct or incorrect treatment decisions. Five diagnostic algorithms were assessed. ELISA was found to make a contribution to the diagnosis of tuberculosis similar to that of sputum smear. Chest roentgenography improved the quality of patient care, but it did so at substantially increased cost. While ELISA did not add to the diagnosis when sputum smear was available, it might be of great use where sputum smear is not available.