The utility of cytopathology testing in lung transplant recipients

Lung transplant recipients routinely undergo bronchoscopy, during which bronchoalveolar lavage (BAL) fluid and transbronchial biopsies are usually obtained. These specimens are typically sent for microbiology, histopathology and cytopathology testing. Cytopathology testing is expensive, and its diagnostic value is questionable. We hypothesized that cytopathology specimens have no additional diagnostic yield beyond that of microbiology and histopathology testing in the routine care of our lung transplant patients.

We reviewed all bronchoscopies performed on a cohort of patients who underwent lung transplantation between February 1999 and August 2002 at our institution. Demographic data, immunosuppressive therapy and the incidence of opportunistic infections in this cohort of 65 patients were reviewed. To ascertain the diagnostic value of cytopathology testing, microbiology and histopathology results from bronchoalveolar lavage and transbronchial biopsy tests were compared with cytopathology results.

Three hundred sixty-six bronchoscopies were reviewed. Microbiologic and histopathology identified 51 cytomegalovirus-, 157 fungus- and 13 mycobacteria-positive specimens as well as respiratory syncitial virus, influenza A and B, enterovirus, actinomyces, Nocardia and mycoplasma. Cytopathology of BAL fluid identified only 3 cytomegalovirus- and 13 fungus-positive specimens. The only unique diagnoses made by cytopathology were 1 case of Aspergillus and 1 unidentifiable fungal element.

We conclude that routine cytopathology testing has little additive diagnostic value in bronchoscopic specimens from lung transplant recipients. Cytopathology results did not alter patient management in any of our 366 cases. Centers should consider discontinuing routine use of cytopathology testing of BAL fluid for surveillance or clinically indicated bronchoscopy, because the yield of this expensive test is extremely low in the setting of lung transplantation.