Study of crystals in synovial exudations with simultaneous determination of adequate enzymes

The paper presents the results of study of 28 synovial exudations in which the uricase method was used for uric acid determination with simultaneous pyrophosphatase and cathepsin C and D activity determination. The presence of crystals in these exudations was investigated as well. From the study follows that a higher uric acid level and higher pyrophosphatase activity coincide with the finding of urate and pyrophosphate crystals. The reported method of examination applies also to other identifications of microcrystals or crystalline split of urates or calcium pyrophosphate dihydrate in the exudation. The activity of cathepsin D permits to conclude on potential participation of peptides and/or polypeptides in the formation of crystals in the exudation.