Deppen SA, et al. - In view of the observation that indeterminate pulmonary nodules (IPNs) on radiography represent granulomas caused by infectious lung diseases, researchers examined the utility of serum biomarkers of histoplasmosis antibodies in the evaluation of IPNs from a highly endemic region. They analyzed a total of 152 serum samples from patients presenting with pulmonary nodules ≤30 mm in maximum diameter for histoplasmosis antibodies by immunodiffusion and enzyme immunoassay (EIA) IgG and IgM tests. In 12% of benign nodules arising from a highly endemic region, a positive EIA test for both IgM and IgG was noted to strongly represent histoplasmosis etiology and benign granuloma. Benign disease was evident in correlation with the presence of either IgG or IgM histoplasma antibodies. Compared to immunodiffusion serology, the EIA test displayed higher sensitivity in assessing histoplasma exposure.