Synovial fluid analysis in the diagnosis of joint disease

Normal synovial fluid consists of a transudate of plasma from synovial tissue blood vessels supplemented with high molecular weight saccharide-rich molecules, particularly hyluronans. This produces in an acellular, aparticulate, viscous, non-clotting semi fluid. During primary inflammatory episodes such as rheumatoid disease and in secondary inflammatory arthropathies such as those caused by bacteria and crystal deposition, changes occur to the cell numbers, cell type, and crystals in the fluid. Endogenous and exogenous debris and particles, particularly those associated with degenerative joint disease, and prosthetic failure can be seen. These changes can be identified and quantified leading to the diagnosis of one of a group of arthropathies or a specific arthropathy. Synovial fluid microscopic analysis is a simple technique that requires little more than a microscope and experience.