Gout is on the rise among U.S. men and women, and this piercingly painful and most common form of inflammatory arthritis is turning out to be more complicated than had been thought. The standard way to check for gout is by drawing fluid or tissue from an affected joint and looking for uric acid crystals, a test known as a needle aspirate. That usually works, but not always: In a new Mayo Clinic study, X-rays known as dual-energy CT scans found gout in one-third of patients whose aspirates tested negative for the disease.

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