Gout without crystals on initial synovial fluid analysis.

In five patients with acute arthritis in whom gout was eventually documented, an initial synovial fluid analysis failed to reveal urate crystals. Four of the patients were seen in one hospital during a period of 30 months in which 103 cases of gout were documented on initial aspiration. While this is an uncommon event, the importance of being able to make a definitive diagnosis of gout is such that re-aspiration of the same or other joints may be justified under certain circumstances.