Western blotting is an efficient tool for differential diagnosis of paracoccidioidomycosis and pulmonary tuberculosis.

Sputum and sera from 134 patients screened for tuberculosis (TB) were analyzed to investigate TB and paracoccidioidomycosis (PCM). Of these patients, 11 (8.2%) were confirmed to have TB, but six (4.5%) were positive only for PCM. All patients with PCM presented anti-43-kDa-component antibodies in Western blotting (WB) assays, while in the TB-positive patients these antibodies did not appear. This preliminary study suggests WB as a potential tool for differential laboratory diagnosis between TB and PCM.