Differentiation of sarcoidosis from tuberculosis using an enzyme-linked immunosorbent assay for the detection of antibodies against Mycobacterium tuberculosis.

This study evaluates the ability of an enzyme-linked immunosorbent assay (ELISA) using adsorbed mycobacterial sonicates as antigen to differentiate between patients with tuberculosis (TB) and patients with sarcoidosis. The study group consisted of 11 patients with active sarcoidosis, seven patients with sputum-positive tuberculosis, and seven normal control subjects. Serum specimens were subjected to ELISA. Serum anti-TB IgG optical density measured at 492 nm (mean +/- SD); pulmonary TB, 0.291 +/- 0.040; normal control subjects, 0.092 +/- 0.011; and sarcoidosis, 0.064 +/- 0.033 (TB vs sarcoid, p less than 10(-6)). This ELISA is a valuable test for the differentiation between sarcoidosis and TB.