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Drs Magliulo and Fumarola correctly point out that our two studies, utilizing the Limulus test to detect endotoxin in the blood of patients with typhoid fever, come to opposite conclusions, but that there were important differences in methodology and sampling of patients that may explain our differing conclusions. Our results showed that 21 febrile Vietnamese patients, 13 of whom had blood cultures positive for Salmonella typhi at the time of sampling, all had negative Limulus tests. Their study showed that nine of 14 Italian patients with positive blood cultures within 12 hours of sampling had positive Limulus tests.The sensitivity of the Limulus lysate used in the two studies was similar, about 1 ng/ml of lipopolysaccharide. In our study, the method of processing plasma to remove protein inhibitors of endotoxin was chloroform extraction. However, in their study, plasma was prepared by acidification with glacial acetic acid, followed by
Butler T, Levin J. Endotoxemia in Typhoid Fever-Reply. Arch Intern Med. 1978;138(10):1579-1580. doi:10.1001/archinte.1978.03630350099029