Utility of bone marrow biopsy for rapid diagnosis of febrile illnesses in patients with human immunodeficiency virus infection

Background. Histochemical staining of bone marrow biopsy samples for microo rganisms may provide a presumptive diagnosis weeks before culture. Methods. To identify predictors of histochemical positivity, we reviewed 16 1 bone marrow biopsies from febrile patients with human immunodeficiency vi rus (HIV) infection. Results, By multivariate analysis, both hematocrit value <30% and white blo od cell count <4,000/mm(3) predicted biopsy positivity by culture or staini ng, but only anemia predicted histochemical stain positivity. Of cases with serum lactate dehydrogenase (LDH) levels >600 U/L, histoplasmosis was diag nosed in 31.6% versus 7.8% with lower LDH levels. Among histoplasmosis case s, staining showed fungi in all, with LDH levels >600 U/L versus 44.4% with lower levels. Conclusions. Bone marrow biopsy will most likely provide a rapid diagnosis in patients with anemia. Markedly elevated LDH levels suggest stain positiv ity for Histoplasma capsulatum. Histopathologic patterns may also guide emp iric therapy.