Technetium-99m Labelled Human Immunoglobulin Scintigraphy Predicts Rheumatoid Arthritis in Patients with Arthralgia

The ability of 99mTc-IgG scintigraphy to predict the development of rheumatoid arthritis (RA) in 47 patients with arthralgia was investigated. 99mTc-IgG scintigraphy and the serum test for rheumatoid factor (RF), measured at the beginning of a year long study, were compared for their ability to predict RA. During the study 8 patients developed RA. The specificity and positive predictive values of RF in predicting RA were 79% and 50% respectively; and for 99mTc-IgG scintigraphy 97% and 88%. The sensitivity and negative predictive values of RF were 100% and of 99mTc-IgG-scintigraphy 88% and 97% respectively. In conclusion, 99mTc-IgG scintigraphy has additional value to RF with respect to the prediction of the development of RA in patients with arthralgia.