Synovial Fluid. I. Comparison of Sodium and Potassium Concentrations in Normal and Diseased Joint Fluid. ∗

Conclusions

1. Data have been presented on the sodium and potassium concentrations of normal human synovial fluid. From the values obtained it is apparent that the normal values for sodium previously reported on material obtained from cattle joints compares favorably with those found in the living human subject and in postmortem fluids. The potassium values were quite variable, using the present technics. In the synovial fluid obtained from rheumatoid arthritics, there was an increase in sodium concentration with a corresponding increase in the synovial fluid/serum ratio for sodium. 2. Technics are described for the collection and analysis of synovial fluid.