Table 1.

Absolute numbers, percentage and 4 × 4 grid for sorting final diagnoses.

N = 300	Final diagnosis FUO/IUO true	Final diagnosis FUO/IUO false
PET/CT positive	True positive: patients with abnormal PET/CT findings that were essential to establish the final diagnosis (N = 162; 54.00%)	False positive: patients with abnormal PET/CT findings that were outruled by other diagnostic methods (N = 10; 3.33%)
PET/CT negative	True negative: patients with normal PET/CT findings with unknown cause for IUO/FUO (N = 88; 29.33%)	False negative: patients with normal PET/CT findings that received a diagnosis by other diagnostic methods (N = 40; 13.33%)