Plain X-rays are usually normal and are not useful for confirming a diagnosis of early gout. They may show signs of chronic gout such as bone erosion. Synovial fluid
A definitive diagnosis of gout is based upon the identification of monosodium urate crystals in synovial fluid or a tophus. All synovial fluid samples obtained from undiagnosed inflamed joints by arthrocentesis should be examined for these crystals. Under polarized light microscopy, they have a needle-like morphology and strong negative birefringence. This test is difficult to perform and requires a trained observer. The fluid must be examined relatively soon after aspiration, as temperature and pH affect solubility. Blood tests
Hyperuricemia is a classic feature of gout, but nearly half of the time gout occurs without hyperuricemia and most people with raised uric acid levels never develop gout. Thus, the diagnostic utility of measuring uric acid levels is limited. Hyperuricemia is defined as a plasma urate level greater than 420 μmol/L (7.0 mg/dl) in males and 360 μmol/L (6.0 mg/dl) in females. Other blood tests commonly performed are white blood cell count, electrolytes, kidney function and erythrocyte sedimentation rate (ESR). However, both the white blood cells and ESR may be elevated due to gout in the absence of infection. A white blood cell count as high as 40.0×109/l (40,000/mm3) has been documented. Differential diagnosis
The most important differential diagnosis in gout is septic arthritis. This should be considered in those with signs of infection or those who do not improve with treatment.
The Tyrannosaurus rex specimen known as "Sue" is believed to have had gout. Research
A number of new medications are under study for treating gout, including anakinra, canakinumab, and rilonacept. Canakinumab may result in better outcomes than a low dose of a glucocorticoid, but costs five thousand times more. A recombinant uricase enzyme (rasburicase) is available but its use is limited, as it triggers an immune response. Less antigenic versions are in development. References
External links

Gout at Curlie
Chisholm, Hugh, ed. (1911). "Gout" . Encyclopædia Britannica. Vol. 12 (11th ed.). Cambridge University Press. pp. 289–291. "Gout". MedlinePlus. U.S. National Library of Medicine.