The authors describe a method to process induced sputum specimens for detection of Pneumocystis carinii which is simple, rapid and inexpensive. Induced sputum and bronchoalveolar lavage (BAL) were obtained within a 24-four hour period from 41 patients who were HIVpositive and had pulmonary symptoms suspicious for P carinii pneumonia. Induced sputum or BAL fluid was placed into Saccomanno's fixative, blended, and centrifuged. The sediment was stained for P carinii cysts by a modified method with Fungi-Fluor Solution A (Polysciences, Warington, PA) and the Genetic Systems Pneumocystis carinii Immunofluorescence Antibody (Genetic Systems, Seattle, WA). The Genetic Systems stain on the BAL specimen was positive in 35 patients and was the standard for comparison. With a single induced sputum, the Genetic Systems stain detected 31 (89%) positive patients, whereas the Fungi-Fluor stain detected 21 (60%). The sensitivity for detecting P carinii cysts in induced sputum was significantly greater (P <.O5) for the Genetic Systems stain. (Key words: Pneumocystis carinii; Induced sputum; Saccomanno's fixative) Am J Clin Pathol 1996; 105: 52-57.In the United States, an estimated 40,000 to 60,000 patients with HIV presented with their first episode of Pneumocystis carinii pneumonia (PCP) in 1993.' Pneumocystis carinii pneumonia is a direct cause of death in up to 24% of patients with AIDS. Without prophylaxis, 60% to 80% of HIV-infected patients will have at least one episode of PCP during their illness.2 Because of the widespread use of primary PCP prophylaxis, the incidence of PCP has been declining, even in patients with CD 4 counts below 200/mm 3 . 3 However, PCP still remains a common opportunistic infection in patients with AIDS.Bronchoalveolar lavage (BAL) performed with the fiberoptic bronchoscope has an excellent yield in the diagnosis of PCP in patients with AIDS.4 "" As the number of patients with AIDS continues to increase, efforts are being made to find alternative methods to BAL for the detection of PCP. Although less sensitive, induced sputum is considerably less invasive, time consuming, and expensive than BAL for detection of P carinii. thermore, it is safer and has less morbidity than fiberoptic bronchoscopy (FOB).Calcofluor white and commercial immunofluorescence antibodies have been used for detection of P carinii. However, there is limited data available on the capability of calcofluor white to detect P carinii in induced sputa, with only seven positive specimens being evaluated. 2021 For immunofluorescent antibody kits that are commercially available, the sensitivity for detection of P carinii in induced sputa has ranged from 86% to 97%.
"23 However, in none of the previously mentioned studies have the recovery of P carinii in both induced sputum and BAL specimens from the same patient been compared.In this study, we have collected both a single induced sputum and a BAL specimen from each patient within a 24-hour period. We describe a method to process induced sputum specimens that is simple, rapid, and i...