Abstract
Two simple qualitative and quantitative microscopic and macroscopic diagnostic methods (the Loose Body Test and the Nucleus Agglutination Inhibition Test) are described. These tests are based on the direct reaction between the L. E. factor and free leucocyte nuclei. As ragards sensitivity, the two methods are superior to the L. E. cell test and the antiglobulin fixation test. The results of an investigation in 800 patients are reported, and the implications of the data obtained are considered.