We agree with Mourad et al1 that, to date, no evidence-based recommendations for the diagnostic workup of fever of unknown origin (FUO) exist, but this is also the case for their proposed approach.1 The spectrum of diseases and the test characteristics are indeed the only available evidence, yet both are flawed. This spectrum is based on data gathered in the 1950s through the 1980s, and this represents a doubtful basis in the present era of ultrasonography, computed tomography (CT), and magnetic resonance imaging.2 The proportion of abdominal abscesses and tumors has decreased in recent series because of the easy detection even by simple ultrasonography, a technique seemingly forgotten by Mourad et al1 in their minimal diagnostic workup and algorithm.
Knockaert DC, Vanderschueren S, Blockmans D. An Evidence-Based Approach to Fever of Unknown Origin. Arch Intern Med. 2003;163(16):1976-1978. doi:10.1001/archinte.163.16.1976-a