Cytologic evaluation of bronchoalveolar lavage specimens in immunosuppressed patients with suspected opportunistic infections.

The role of bronchoalveolar lavage cytology in the diagnostic evaluation of immunosuppressed patients with suspected opportunistic pulmonary infections was evaluated by comparing two groups of patients who underwent fiberoptic bronchoscopy. Bronchoalveolar lavage specimens were compared with other available diagnostic techniques, including bronchial washings, bronchial brushings, transbronchial lung biopsies and open lung biopsy. Prior to the initiation of a protocol for bronchoalveolar lavage, a specific etiology for the pulmonary infiltrate using the above combined modalities was identified in 23 of 47 cases, for an overall diagnostic rate of 49%. The combined bronchial washings and brushings (cytologic procedures) identified a specific etiology in 9 of 47 (19%) of the cases. There were ten cases in which a cytologically identifiable organism (Pneumocystis, virus or fungus) was not present in the bronchial washings and brushings and one missed case of malignancy, for a false-negative rate of 23%. With the addition of the lavage technique and better sampling of the distal airways, a specific etiology for the pulmonary infiltrate was identified in 32 of 48 (67%) of the cases. This is comparable to the values of 40% to 65% cited in the literature for diagnosis of infectious disease by open lung biopsy. The lavage cytologic procedure identified a specific etiology in 22 of 48 (46%) of the cases, and the false-negative rate was reduced to 6%. With the excellent sampling of the bronchoalveolar lavage and the improved cytology results, the need for transbronchial or open lung biopsy has been eliminated in immunosuppressed patients with suspected opportunistic pulmonary infections. This allows these patients to be studied on an outpatient basis.