Analysis of bronchoalveolar lavage specimens from immunocompromised patients with a protocol applicable in the microbiology laboratory.

Several studies have concluded that bronchoalveolar lavage (BAL) is a useful technique for diagnosing pulmonary disease in immunocompromised patients, but implementation of a protocol for obtaining, processing, and analyzing BAL specimens in a clinical microbiology laboratory has not been reported. We determined the utility of a laboratory protocol by analyzing 100 BAL specimens from 94 immunocompromised patients. Each BAL specimen was cultured quantitatively for bacteria. A concentrate of each specimen was cultured for fungi, viruses, mycobacteria, and Legionella sp. Slides of the BAL concentrate were prepared by cytocentrifugation and stained by a number of histochemical and fluorescence techniques. Overall diagnostic yields of 81% for infections, 90% for hemorrhage, and 13% for neoplasms were obtained with the patients studied. BAL analysis was incapable of diagnosing drug- or radiation-induced pneumonitis or idiopathic interstitial pneumonitis. After evaluation of the protocol was completed, it was successfully implemented in two university-based clinical microbiology laboratories as a routine diagnostic service.