This study addresses the problems connected with knee joint inflammatory swelling diagnosis, especially cases which have difficulty meeting rheumatic and laboratory criteria. A percentage of patients were considered who met the clinical criteria of the Association of Rheumatoid Arthritis (ARA), proceeded without any deviations within the range of rheumatoid factor (RF) laboratory results, and where only serum non-specific immuno-complexes (CIC) increased. The decision to execute a more effective treatment variant (salazopirin, for example, instead of NSAID), required criterial reliability in practice. The purpose of the study was to attempt to find physiochemical distinguishing features in the exudative liquid taken from the knee joints of two groups of patients: group A meeting the clinical criteria of immunological inflammation and a negative rheumatoid factor, and group B with other inflammation concerned with degenerative changes and with negative rheumatoid factor tests. The main area of interest was the question of whether dielectric scanning enables the distinction between immunology and degenerative inflammatory liquid. Analyses of dielectric joint liquid parameters in the domains of frequency and temperature made it possible to observe recurring changes in the shapes of diagrams in the event of the existence of immunological complexes in the studied environment. We found that (1) dielectric scanning diagrams after joint liquid analyses showed similar negative dielectric parameters in group A (inflammatory), B (degenerative) and C (post-accident) with scanning frequencies of about 10,000,000-3501,300 Hz and similar positive parameters of about 3501,300-1593,700 Hz, but qualitative difference dielectric parameters in group A with a frequency of 1593,700-1225,900 Hz, probably dependent on the inflammatory gamma-globulin concentration; (2) higher dielectric parameters (groups B, C) at a scanning frequency of 94,300-57,600 Hz probably dependent on ion concentration; (3) parametric changes of frequency scanning differentiating the diagrams between groups A and B, C, defining the outline pilot study recommended ranges of frequency and temperature testing for further investigations.