Diagnosis of Pneumocystis carinii pneumonia by induced sputum in a city with moderate incidence of AIDS.

Examination of induced sputum from AIDS patients has been reported to provide the noninvasive diagnosis of PCP in 10 to 76 percent of cases. Since previous studies were done in centers with a high incidence of AIDS, we asked whether this test could be implemented successfully in a center with a lower incidence of AIDS. Over a 13-month period 25 of 38 (66 percent) AIDS patients with PCP had positive Giemsa (Diff-Quik) stains of induced sputum. We were unable to predict before sputum induction which patients would be positive based on clinical severity (increased A-a gradient or serum LDH levels). We confirmed prior observations that a normal serum LDH level was found in only 5 percent of documented PCP cases. This noninvasive technique significantly decreased the number of bronchoscopies performed and led to a considerable cost savings.