Significance of Urate Crystals in Synovial Fluids

Abstract

Recent reports by Hollander and his coworkers^1-2 have stressed the diagnostic potentiality of synovial fluid examination in patients with gouty arthritis. These authors have pointed out the significance of the finding of urate crystals in joint fluid. By ordinary light microscopy the crystals appear as short, rod-like structures with parallel sides and rounded ends (Fig. 1). By polarized light they can be seen to be negatively birefringent and appear as discrete bright rods against a dark background (Fig. 2). McCarty has shown that the crystals disappear after enzymatic digestion by uricase.² This report is based on 27 observations of the synovial fluids from 22 patients with gout and confirms the specificity of the finding of urate crystals in patients with gouty arthritis. Materials and Methods Synovial fluid was obtained from the affected joints of 22 patients with gout. The diagnosis of gout was made without reference to the