Oxalic acid level in bronchoalveolar lavage fluid from patients with invasive pulmonary aspergillosis.

Oxalic acid is a fermentation product of Aspergillus. We have measured the oxalic acid level in bronchoalveolar lavage fluids recovered from immunocompromised patients with and without invasive pulmonary aspergillosis. These levels were significantly higher in patients with invasive aspergillosis than in patients with pneumonitis of other causes. Thus, the determination of oxalic acid in bronchoalveolar lavage could be a presumptive argument for invasive aspergillosis until positive fungal cultures or histologic diagnosis; its potential value in monitoring the course of invasive pulmonary aspergillosis, particularly under treatment, has to be confirmed in more patients.