Serum Lactate Dehydrogenase (LDH) in Pneumocystis carinii Pneumonia, Tuberculosis, and Bacterial Pneumonia

An increase in serum lactate dehydrogenase (LDH) activity is commonly taken to support the presumptive diagnosis of Pneumocystis carinii pneumonia (PCP), although the LDH level may also be increased in other lung infections and in a variety of extrapulmonary disorders. To assess its diagnostic value in patients with fever, lung infiltrates, and a high prevalence of HIV infection, we compared LDH levels in 42 hospitalized patients with PCP, 71 with disseminated tuberculosis (TB), 40 with pulmonary TB, and 37 with bacterial pneumonia. Peak LDH level was higher (p (CHEST 1995; 108:415-18)