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.