Utility of the lateral chest radiograph in the evaluation of patients with a positive tuberculin skin test result.

STUDY OBJECTIVES In the United States, chest radiographs are performed on patients with positive tuberculin skin test (TST) results. It is not known whether, in addition to a single posteroanterior radiograph, a lateral chest radiograph is clinically indicated or cost-effective. We sought to determine the utility of the lateral chest radiograph in evaluating TST-positive adults. DESIGN Cross-sectional study. SETTING Tertiary-care hospital. PATIENTS Adults with positive TST results. MEASUREMENTS Findings on posteroanterior radiographs alone were compared to posteroanterior and lateral chest radiographs. RESULTS In 2 of 535 cases (0.4%), lateral chest radiographs revealed a calcified granuloma not visible on posteroanterior radiographs. This finding did not alter patient management. In all other cases, lateral radiographs only confirmed findings seen on posteroanterior chest radiographs. CONCLUSION Treatment altering findings were always visible on posteroanterior radiographs alone. These results suggest that lateral chest radiographs are not useful in evaluating adults with positive TST results.