Marrow biopsy in the diagnosis of pyrexia of undetermined origin

Marrow from 62 cases of pyrexia of undetermined origin was examined cytologically, histologically, and bacteriologically. Diagnostic findings were present in five cases (8%), but all these patients presented definite clinical or haematological indications for marrow biopsy. It is concluded that marrow examination is useful in the diagnosis of pyrexia of undetermined origin but that cases for study must be selected in the light of general principles. Fever alone, even though prolonged and undiagnosed, is not an indication for marrow biopsy.