Diagnostic utility of lactate dehydrogenase levels in patients receiving aerosolized pentamidine.

Serum lactate dehydrogenase (LDH) levels are elevated in patients with Pneumocystis carinii pneumonia (PCP). In patients receiving aerosolized pentamidine (AP), PCP may be less severe and present with more localized radiographic infiltrates. We evaluated the diagnostic utility of the serum LDH level in 11 patients developing PCP while receiving AP. Serum LDH levels were increased 72.7 +/- 19.0 percent over mean baseline levels and 76.4 +/- 26 percent over the upper limit of normal value for our laboratory with the development of PCP. An elevated serum LDH value remains a useful diagnostic adjunct in the patient developing PCP while receiving AP. Isolated LDH values must be interpreted with caution given the potential for marked variability in the baseline LDH value.