Indium leucocyte imaging in true pyrexia of unknown origin

A patient with pyrexia of unknown origin (PUO) was investigated for a focal infection using autologous indium-labelled leucocytes. Only one site of increased activity was observed; this was asymptomatic and subsequently proved to be an infected nasal sinus. This case highlights the necessity, in PUO investigations, of carrying out whole-body imaging rather than just investigating the areas with presenting symptoms.