A 58-year-old man has the sudden onset late one evening of severe pain in his left great toe. There is no history of trauma. On examination there is edema with erythema and pain on movement of the left 1st metatarsophalangeal joint, but there is no overlying skin ulceration. A joint aspirate is performed and on microscopic examination reveals numerous neutrophils. Over the next 3 weeks, he has two more similar episodes. On physical examination between these attacks, there is minimal loss of joint mobility. Which of the following laboratory test findings is most characteristic for his underlying disease process?

Many patients with gout will have hyperuricemia, but not all. The big toe is the most common joint involved with gout. Acute gouty attacks are associated with intense pain from acute inflammation. Incorrect 1. Hyperglycemia is a feature of diabetes mellitus, which is associated with peripheral vascular disease that increases the risk for foot ulcerations and osteomyelitis. Incorrect 2. The arthralgias common to many autoimmune diseases with a positive ANA, such as systemic lupus erythematosus, are not usually associated with joint swelling, redness, or deformity. Incorrect 4. There can be bone luceny with hyperparathyroidism, but the joints are not greatly affected, nor is there swelling or redness.