Utility of Gomori methenamine silver stains in bronchoalveolar lavage specimens.

Bronchoalveolar lavage (BAL) with Gomori methenamine silver (GMS) stain is commonly used to detect Pneumocystis carinii and fungal organisms as causes of infectious pulmonic disease in immunosuppressed patients. However, several reports have indicated that GMS stains are not any more sensitive than conventional cytologic stains in detecting Pneumocystis organisms in select patient populations, such as those with acquired immunodeficiency syndrome (AIDS). To examine the utility of GMS stains in our laboratory, we retrospectively reviewed 243 BALs from 188 patients. Sensitivity of the GMS stain for Pneumocystis and for fungi detection was 100%. Sensitivity for Pneumocystis and for fungi detection by Papanicolaou stain alone was 79% and 88%, respectively; by Diff-Quik stain alone it was 68% and 88%, respectively; and by combined Papanicolaou and Diff-Quik stains it was 79% and 100%, respectively. In four additional cases, fungi were detected by other methods (culture, biopsy) and not by BAL. The GMS stain result was correlated with a number of risk variables to determine which variables were associated with GMS positivity. Using stepwise logistic regression, Pneumocystis positivity by GMS stain correlated (P < 0.0001) only with the variable of history of AIDS or AIDS risk factors. Fungal organism positivity by GMS stain correlated (P = 0.02) only with the variable of history of BAL positivity for fungus. Cost savings analyses were performed, estimating the cost of the GMS stain at $45 (total cost of GMS in 243 BALs was $10,935).(ABSTRACT TRUNCATED AT 250 WORDS)