USE OF IMMUNOSCINTIGRAPHY IN THE DIAGNOSIS OF FEVER OF UNKNOWN ORIGIN

Fever of unknown origin (FUO) has been defined as an elevation in temp erature (38-degrees-C) for at least 2-3 weeks despite intensive invest igation. The value of immunoscintigraphy with the technetium-99m-label led anti-granulocyte antibody anti-NCA-95 (BW 250/183, IgG1) was studi ed retrospectively in 34 consecutive patients with FUO. Every effort w as made to confirm a diagnosis, including methods such as ultrasonogra phy, computed tomography, magnetic resonance imaging, bacteriological tests, surgical intervention and clinical follow-up. In 58.8% of the p atients, an infectious cause for the fever was found, in 30.2% of the patients, a benign or malignant haematological disease, pancreatitis o r thyrotoxicosis was found. No cause for fever could be found in 11%. The overall diagnostic sensitivity and specificity of immunoscintigrap hy for infection were 40% and 92% respectively. The positive predictiv e value was calculated to be 88% and the negative predictive value was calculated to be 52%. False-negative scans were especially noted in p atients with endocarditis, pneumonia and small brain abscesses, where the lesions did not exceed a diameter of 0.5 cm. If patients with endo carditis were excluded, the imaging sensitivity and specificity were i ncreased to 57% and 95%. This study demonstrates that 99mTc-anti-NCA-9 5 scanning is able to localize infectious causes of FUO, other than en docarditis.