title: False negative biopsy in Pneumocystis carinii pneumonia.
abstract: Unlike most pneumonias, the diagnosis of Pneumocystis carinii pneumonia is based solely on identifying organisms by stain, usually with methenamine-silver. Because of technical problems involved with adequate staining, control samples usually are done concurrent with tissue specimens to be examined. Lung containing fungi often is used as a control. We recently observed false-negative biopsy specimens in a case of P carinii pneumonia where the Pneumocystis organism failed to stain with methenamine-silver on several occasions, although fungal controls were positive. This report emphasizes the importance of using P carinii as a control whenever attempting to diagnose P carinii pneumonia.
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008168:Lung / Q000382:microbiology*; D011010:Pneumocystis / Q000302:isolation & purification; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis* / Q000382:microbiology; D013194:Staining and Labeling