title: Serum LDH level as a clue to the diagnosis of histoplasmosis.
abstract: The purpose of this study was to determine whether serum lactate dehydrogenase (LDH) level could be used as an adjunct clinical marker to differentiate between histoplasmosis and Pneumocystis carinii pneumonia (PCP). In a retrospective, case-controlled study, 30 patients with a diagnosis of histoplasmosis (all but 1 with disseminated disease) were compared with 120 patients with PCP (33 patients with definitive PCP, 87 with presumed PCP). Groups were matched for CD4+ lymphocyte counts, sex, and year of diagnosis. The mean LDH level for patients with histoplasmosis was 1068 +/- 197 IU/L; for PCP, it was 375 +/- 23. An LDH level of more than 450 IU/L was 9.33 times more likely to be associated with a diagnosis of histoplasmosis than with PCP (odds ratio [OR], 9.33; 95% confidence interval [CI], 3.50-25.47; P < .01), and an LDH level of more than 600 IU/L was 9.41 times more likely to be so (OR, 9.41; 95% CI, 3.43-26.31; P < .01). An LDH level of 450 IU/L or greater had a sensitivity and specificity of 70% and 80%, respectively; a value of 600 IU/L or greater had sensitivity and specificity of 50% and 89%. Thus, serum LDH levels of 600 IU/L or greater are suggestive of histoplasmosis rather than PCP in appropriate clinical settings. Serum LDH may serve as an adjunct laboratory marker in the diagnosis of histoplasmosis. Elevated levels may prompt the physician to look for a diagnosis other than PCP early in the course of the illness.
authors.affiliation: University of Pittsburgh, ID-HIV Clinics, Pittsburgh VA Healthcare System, Pittsburgh, USA.
authors.forename: Adeel A
authors.initials: AA
authors.lastname: Butt
authors.forename: Stephanie
authors.initials: S
authors.lastname: Michaels
authors.forename: Donald
authors.initials: D
authors.lastname: Greer
authors.forename: Rebecca
authors.initials: R
authors.lastname: Clark
authors.forename: Patricia
authors.initials: P
authors.lastname: Kissinger
authors.forename: David H
authors.initials: DH
authors.lastname: Martin
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D006660:Histoplasmosis / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood*
chemical_list: D007770:L-Lactate Dehydrogenase