The presence of crystals (microscopic solids that form distinct lattices, with definable fixed angles, faces, walls) in the joint (synovial) fluid.
Comment:
Polarized light microscope is the standard method for synovial fluid analysis in the search for crystals. Identification of monosodium urate and calcium pyrophosphate crystals in synovial fluid samples obtained from inflamed joints allows the precise diagnosis of gout and calcium pyrophosphate dehydrate crystal related arthropathy